Preheat the oven to 350° F. Grease a 9×13–inch baking dish with cooking spray and set aside. In a large skillet, heat the olive oil over medium-high heat. Add the onion, garlic, and jalapeño. Sauté until softened, about 5 minutes. Add in the peppers and corn. Cook for 3-4 minutes more. Add the lime juice, cumin, chili powder, cilantro, salt, and pepper (to taste) and stir. In a large bowl, add the cooked quinoa and black beans. Add the onion mixture, enchilada sauce, and ½ cup shredded cheese and mix. Pour the quinoa and black bean mixture into the baking dish. Top with the remaining cheese. Cover the baking dish with foil. Bake for 20 minutes. Remove the foil and bake until the cheese is melted and edges are bubbling, about 10 minutes more. Remove from the oven and let cool for 10 minutes. Garnish with toppings, if desired. Serve warm.