Peel the sweet potato, and chop into small pieces. Boil until very soft (approx. 15 minutes). Drain, and mash. Mix in the Chili powder, Cilantro, and salt.
Cook frozen corn, according to package instructions.
Spread 1/4 cup of the sweet potato mixture on the first tortilla. Cover with 1/4 cup of black beans, and 1 tbsp. of corn, spreading evenly. Sprinkle with 1/4 cup shredded cheese. Cover with second tortilla.
Spray frying pan with cooking spray. Fry quesadilla for a few minutes on each side, until cheese is melted, and beans are heated through. Slice into quarters.