My kids like:
Creamy tuna and peas - make a pint of savoury white sauce using a chopped onion and some garlic, mix in a tin of tuna and about 1lb of thawed frozen peas. Season with plenty of black pepper and serve over mash.rice/baked potatoes.
TUna lasagne - cook a chopped onion and garlic in some oil until soft. Add 2 tins of tomatoes and cook until saucy. Chuck in some spinach, nutmeg, mixed herbs and cook a few minutes. Stir in a 400gm tin of tuna and a handful of prawns, if you like them. SHake over some lemon juice and season to taste. Layer with lasagne sheets and top with some cheese sauce.
TUna puff pie - butter 8 slices of bread. Lay four of them in the bottom of a lasagne type dish. Sprinkle a tin of tuna over the bread and then about 4oz grated cheese. Put the other 4 slices of bread on top so you have sandwiches. Beat 4 eggs into a pint of milk with salt, pepper, mustard and some parsley. Pour over the bread and sprinkle with a little more cheese. Leave aside for about 1/2 an hour and then bake at 180 for about 1/2 an hour or until set, puffy and golden.
Tuna on toast - fry an onion and some garlic until soft. Stir in a tin of condensed mushroom soup and 1/2 a soup can of milk. Stir until smooth and heated through. Chuck in a tin of tuna and a big tin of peas or sweetcorn. Season to taste and heat through. Pour over toast. Or you can use it as a pasta sauce or a topping for mash.
Tuna and chick pea burgers - mash a couple of tins of chick peas with a tin of tuna, some cumin, coriander, chilli, a handful of breadcrumbs and an egg and make burgers.
Tuna fishcakes
Fishy fritters - mix tuna/salmon with corn and cooked noodles. Add an egg, milk and flour to make a batter and fry in tablespoonfulls like drop scones.
TUna pasta salad - cold cooked pasta, tuna, corn, onion, red pepper, mayo and lemon juice.
Tuna wedge melt - 2lbs potato wedges or oven chips, almost fully cooked. Mix a 400gm tin of tuna with 1/2lb grated cheese, a finely chopped onion, 3 or 4 tablespoons may, lemon juice, chopped parsley and black pepper. Spread over the cooked wedges and bake at 180 for about 20 minutes. You can add some sweetcorn to the mix as well, if you like.
Tuna rice salad - cold, cooked rice, tuna, onion, corn, cucumbers, red peppers, cherry toms, oil and vinegar dressing, salt pepper and finely chopped chilli
Tuna pie - mix with fried onion, tin tomatoes, tin baked beans and top with mashed potatoes.
TUNa pie - mix with mushrooms, onions, corn and thick white sauce, top with pastry.
Mix it with sweetcorn, onion, tomatoes and mayo and serve in baked potatoes
TUna curry - fry an onion with 1/2 a jar of curry paste. Add 2 tins of chopped tomatoes and cook until saucy. Stir in a 400gm tin tuna and mix about then add a couple of sachets of creamed coconut and some peas.
Oh dear, I didn't realise that I had so many different tuna things 
we don't eat it all the time, honest.