tuna sandwich recipe

Ingredients: 1 can (5 oz) tuna, drained 2 tablespoons mayonnaise 1 tablespoon Dijon mustard (optional) 1 celery stalk, finely chopped 2 tablespoons red onion, finely chopped 1 tablespoon relish or chopped pickles (optional) Salt and pepper, to taste 4 slices of bread (whole wheat, white, or your preference) Lettuce leaves