Tuna Melt Sandwhich

Drain the water from the tuna. In a bowl, add the drained tuna, mayo, pickles, red onion, dijon mustard, lemon juice, salt and pepper. Use a fork to flake the tuna apart and mix until well combined.
Spread a thin layer of butter on one side of each bread slice. Spread the tuna salad evenly over the unbuttered sides of two slices of bread. Top with 1 or 2 slices of cheese and top with the remaining bread, buttered sides facing up.
Heat a large skillet over medium-low heat. Add the sandwiches to the pan, cover with a lid, and cook for about 3-4 minutes. Using a spatula, flip the sandwiches and cook for another 3-4 minutes or until the cheese is melted and the bread is crispy and golden. If your pan is smaller, you may need to cook one sandwich at a time.
Using a spatula, transfer the sandwiches to plates and cut in half.