Preheat oven to 375. Toss cheese and chili powder in large bowl until well blended. Add beans, onion and cilantro and toss to blend.
Arrange 2 tortillas on baking sheet. Press half of cheese filling over each tortilla, leaving 3/4 inch border at edges. Firmly press second tortilla atop each. Bake until cheese melts and filling is heated through, about 10 minutes.
Cut each quesadilla into 6 wedges. Transfer wedges to plates and serve.