Celery, fresh dill and a little Dijon mustard make a tuna sandwich fancier, and if you like spice, then try mixing in some salsa and a little diced green chile. Spoon over baked tortilla chips and sprinkle with cheese, then place under the broiler until cheese melts. Replacing high-fat ground beef with tuna can make a great lower-fat burger - mix a can of tuna with two egg whites, 1/4 cup plain oatmeal and a sprinkle of garlic, onion powder and pepper. Form into a patty, then brush with BBQ as you cook in a skillet. Use your favorite fixings on a whole-wheat bun for a satisfying burger fix.