In a bowl, combine all of the ingredients for the tuna salad and mix well. Cover and refrigerate until you are ready to make the sandwiches.
Set the oven on low broil.
Place 7 slices of rye bread on a baking sheet.
Spoon the tuna salad evenly on the slices of bread.
Top with a slice of swiss cheese, a tomato slice and a slice of cheddar cheese.
Leave the sandwiches open-face, but place the remaining bread slices on the baking sheet to allow them to lightly toast.
Place the baking sheet in the hot oven and heat for 3-5 minutes or until the cheese is melted.
Remove the baking pan from the oven.
Add lettuce slices if desired and top with the toasted bread slices.
*To toast both sides of the bread, use a baking screen. This will allow air to circulate under the bread and toast it lightly. If you’d like toasted bread and don’t have a baking screen, simply toast the bread in a toaster before putting the sandwiches together. Then warm in the oven as described above.*The exact number of sandwiches will depend on how big your bread slices are. If the bread is large, we recommend 7 slices and cutting them in half.