Heat the olive oil in a large nonstick skillet over medium-high heat until hot. Add the sliced mushrooms, chopped bell pepper, and onion, and saute 4 minutes or until the mushrooms are tender. Add the chopped chicken, chili powder, and ground cumin, and saute 2 minutes or until thoroughly heated. Spread about 1/2 cup chicken mixture over each of 4 tortillas, and top each with 2 tablespoons cheddar cheese and remaining tortillas. Coat skillet with cooking spray, and place over medium heat until hot. Add 1 tortilla to skillet, and cook for 3 minutes on each side or until lightly browned. Remove from skillet, and keep warm. Repeat the procedure with the remain-ing quesadillas. Cut each quesadilla into 3 wedges. Serve with Cranberry-Mango Salsa.