Heat oven to 450°F. Coat a baking pan with cooking spray. In medium bowl, combine black beans, corn, and cilantro.
Place 1 tortilla in pan. Spread 1/3 of salsa over tortilla. Top with 1/3 of bean mixture and 1/3 of cheese. Layer 2 more times, finishing with last tortilla.
Bake in oven 12 to 15 minutes, or until cheese melts and filling is hot. Serve with sour cream, if desired.