Heat refried beans in the microwave until smooth. Stir in salsa.
Lay 6 flour tortillas down flat. Spread 1/6 of the bean mixture over each tortilla. Sprinkle 1/4 cup of shredded cheese on top. Top with the remaining tortillas.
Heat a skillet over medium heat and lightly grease with non-stick cooking spray. Cook quesadillas for 3-4 minutes on each side, until lightly browned and the cheese has melted.