I love a good tuna salad melt sandwich. I think it's one of the best yet easiest sandwich to make. The preparation is not complicated at all and it's so flavourful.
Preheat the broiler to high. In a bowl, break up the tuna a little with a fork.
Add the tuna to a large bowl with the celery, scallion, parsley, capers, mustard and mayonnaise. Mix until combined, making sure everything is coated in the mayo. Taste it before seasoning with salt and pepper since the capers are already salty.
Place the toasted rye bread slices on a sheet pan. Top each with a third of the tuna and 1 ounce of shredded cheese.
Place the sandwiches under the broiler for about 2 to 3 minutes, frequently checking, until the cheese has melted and become bubbly. Remove the sandwich melts and allow to sit for 30 seconds before slicing each tuna melt in half. Serve immediately, with a few varieties of hot sauce for dribbling.