In medium bowl, combine tomatoes, corn and cilantro; mix well.
Spread each of 8 tortillas with 2 tablespoons refried beans. Top each of remaining 8 tortillas with 1/4 cup cheese and scant 2 tablespoons corn mixture; spread evenly. Cover each with 1 bean-covered tortilla, bean side down.
In large nonstick skillet over medium heat, heat 1 quesadilla for 1 to 2 minutes on each side or until cheese is melted and tortilla is toasted.* Remove quesadilla from skillet; repeat with remaining quesadillas.**
To serve, cut each quesadilla into 4 wedges. If desired, serve with nonfat sour cream and salsa.