try adding dill and capers, maybe a dash of lemon juice or Worcestershire sauce.

Use Cajun seasoning powder (Tony chacheres is my go to), and lemon pepper, a large spritz of lemon, and mix Frank's red hot in with your mayo (I've not tried Kewpie Mayo, maybe you don't want to pollute it). Some red chili flakes and Italian seasoning, maybe some garlic or onion powder, is my tuna mixture for tuna melts.

(I am in no way a chef, but this is what I make when it's my turn to cook)

For something totally different: tuna patties

• 2 cans of tuna, drained
• 1 egg
• 1 sleeve of saltine crackers, crushed and divided
• Worcestershire sauce, optional
• Favorite frying oil

Crush crackers into crumbs. Set aside approximately 1/3-1/4 to bread patties. Put remainder into a bowl. Add egg and drained tuna. Add a few dashes of Worcestershire sauce if desired. Mix together and form patties. (I usually get 2 to 4 patties per can.) Coat outside with cracker crumbs, fry in oil until outer crackers are golden brown. Serve and eat.

Can also be made with canned salmon. My kids like eating them with ketchup or steak sauce. This is actually what I'll be making for supper tomorrow night. You could totally eat this up with spicy ketchup.

My go-to can-of-tuna meal is two 5-oz cans (or one 12-oz can), a heavy dollop of mayo, and a spoonful of sweet relish. Stir it all up, serve in a bowl.

This used to be my standard recipe for tuna fish sandwiches, but then I figured, why add bread? That's just extra calories. I'd rather have a bit more mayo than two slices of dry bread.

EDIT: I prefer two 5-oz cans because I squeeze out all the water from the cans (open with can opener, use lid to compress and squeeze out water) and it's harder to squeeze out most of the water from the large 12-oz can. Two smaller cans works better. I don't like my tuna watery. My wife does, though; she says it adds a stronger tuna-y flavor to the dish.

Soy sauce, chili sauce, chili crisps, rice vinegar, curry powder, or any combination of them. Adding scallions or grapes is also good (maybe not both, never tried it).

Lemon juice, pepper, and parmesan is also good.

Both of the above assume some mayo is used as a base binder.

Basically fat, acid, salt, and heat (in this case spice, but you can also add bread crumbs and egg to make tuna cakes)

When I was living on the road, I used to enjoy making what I'd call "Poor Boys".

Tuna + Mayo. Put it in a hotdog bun, along with a leaf of lettuce.

If you're already putting it into onigiri, try adding pickled plum or pickled ginger

Probably not what you're looking for but also a neat camping trick so here it is.

Partially open the lid, stuck a folded paper towel inside it so it soaks up the oil and light it on fire. It'll burn for several minutes and you can use that heat to cook something else.

At the end remove the paper towel and the tuna will have been cooked nicely.

This was my college-era budget-stretcher:

Mix into 1 can of tuna (in water), drained ...

• Equal parts Hellmann's Organic Mayonnaise* and Inglehoffer Original Stone Ground Mustard*.
• 1-2 diced Claussen Hearty Garlic Pickles*.
• Sliced pepperoncini.
• Salt, pepper, cayenne to taste.

... and serve with toast or crackers.

*These are my brands. Just use whatever you got.

Chopped pickles and hot sauce with the.mayo is my go to answer. Or chopped smoked Chipotle in Adobo sauce. Veg like tomato and celery also work well.

Swap you can of tuna with salmon, but don't tell yourself.

Maybe add some sliced grapes or chopped walnuts? Or if you want something fermented/pickled maybe add some chopped up kimchi? I bet some radish kimchi would give it a nice crunch

Garlic salt.

Take a look at the flavored pouches of tuna. They're comparable price to the cans, but they don't need to be drained.

Grew up in the southern US where we pretty much treated canned tuna as a conduit for mayonnaise & an excuse to eat ritz crackers for dinner.

Given that, I took to just adding diced tomatoes to the mix, which at least gave the meal a hint of nutritional value.

Not sure how well that combo works with onigiri, but thought I’d put it out there.

I used to use tuna to make my typical Mac and cheese more filling so you can go that route.

However, since you were mentioning rice I would add some kimchi, rice wine vinegar and sesame seeds.

Pickle some red onions to go with it. Drop in a chili or two into the brine for some spice.

If you want to get really crazy, try making your own mayo, too. It's not as hard as you think and you can control the flavors.

Sounds like tuna salad, which is delicious. Add spring onion or red onion or whatever oniony thing you want. Possibly a bit of celery if you're into that (small pieces so it's not stringy).

Try some citrus zest and/or juice. The juice is only if the rice isn't too acidic already.

Oh, and if you're into spice, sriracha goes on a lot of different things - it is chili sauce with vinegar and garlic, which seems like a good fit. If that isn't your thing, you can still bring the spice level up with cayenne or whatever chili flake. "Chili powder" could work but often has some un-onigiri-like extra spices.

Fermented and spicy - how about some gochujang? It's like miso, but a Korean version with chili. Mix it with some good sesame oil and a splash of rice vinegar to lighten it up. Then put it with the tuna in your onigiri like you would the mayo. It's already salty, so no need to add salt.

For something in the other direction, try chopping dates and adding them to your tuna.

I used to eat a pasta sauce with canned tuna that also had onion, yoghurt (or cream) and capers. Depending on the amount of effort you want to put in, maybe just adding some capers might work :)

My mom used to make hot potato and tuna salad. It was one of my favorites growing up. It was boiled potatoes, relish, tuna, mayo, salt and pepper, served warm. Really tasty.

Tuna casserole is another tasty option.

If you want to go an Asian route, you can do tuna served on rice with some chili crisp and sliced cucumber.

BBQ sauce. Tastes like pulled pork.