Special equipment: a waffle maker
Preheat a waffle maker to the regular setting according to the manufacturer's instructions.
Sprinkle the cheese on 1 tortilla, add the salsa and place the second tortilla on top. Spray the waffle maker with the cooking spray. Place the quesadilla on the waffle maker, close the lid and cook until the cheese melts, 2 to 3 minutes.
Slice and serve.