Place the two slices of bread on a clean surface. Lay the cheese slice on one piece of bread. Top the cheese with the ham, turkey pepperoni, and thin sliced red onion.
Carefully place the other slice of bread on top.
Spray the panini maker with nonstick cooking spray. Add the sandwich and close the panini maker.
Let the sandwich cook for 2-3 minutes, or until the bread is golden and crispy.
Add the shredded lettuce to a bowl and toss it with 1 tablespoon of light Italian dressing.
Carefully remove the panini from the press using a spatula. Place it on a cutting board and remove the top piece of bread.
Add the lettuce, tomato, and banana peppers. Place the top piece of bread back onto the sandwich and enjoy!