Preheat your oven to 400°F. Pierce the sweet potatoes several times with a fork, place them on a baking sheet, and roast for 45-50 minutes until they are very soft and easily pierced with a knife.
Scoop the warm sweet potato flesh into a medium bowl, discarding the skins. Mash the sweet potato with a fork until smooth, then stir in the olive oil, chili powder, cumin, garlic powder, and salt until fully combined.
Add the drained black beans, thawed corn, red onion, and cilantro to the sweet potato mixture. Stir gently until all the ingredients are evenly distributed throughout the filling.
Lay a tortilla flat on a clean work surface. Spread about ½ cup of the sweet potato filling evenly over one half of the tortilla, then sprinkle with ¼ cup of shredded cheese. Fold the other half of the tortilla over to create a half-moon shape.
Lightly coat a large non-stick skillet or griddle with cooking spray and heat over medium heat. Cook the quesadilla for 2-3 minutes per side, until the tortilla is golden brown and crispy and the cheese inside is fully melted. Repeat with the remaining tortillas and filling.