Mix together the tuna, mayonnaise and sweetcorn in a small bowl. Spoon the filing into the two rolls, wraps or pitta breads and serve. For extra fillings you could add lettuce, grated carrot ...
Top tuna with cheese, packing it on generously, and slide sandwiches under broiler. Broil until cheese melts and bubbles, 4-5 minutes. Remove tuna melts from broiler and serve immediately.