Preheat the oven to 375 degrees F. Lightly grease a 9 x 13 baking dish or rimmed baking sheet. Spritz the peppers with the cooking spray and lay out in the dish/sheet.
Place a large skillet over medium-high heat and add the olive oil. Once oil is shimmering, add the sweet potato noodles and season with salt and pepper. Cook for 5-7 minutes or until mostly wilted (they don’t need to be fully cooked, because they will cook longer in the peppers.) Add the quinoa, tomatoes, cayenne, paprika, onion powder, cumin, chili powder, garlic powder, black beans, and corn. Season with salt. Mix together.
Stuff the peppers with the quinoa mixture until all peppers are filled. If using cheese, sprinkle each pepper with cheese. Once peppers are filled to your preference, cover the dish/sheet with foil.
Bake the peppers for 20 minutes and then remove the foil and bake for another 10-15 minutes or until peppers start to slightly brown.
Remove the peppers from the oven, garnish with cilantro, and serve with avocado.
Per Serving (1 stuffed bell pepper halve ((out of 12)) - Calories: 163, Total Fat: 6g, Sodium: 173mg, Carbs: 23g, Fiber: 8g, Sugars: 2g, Protein: 6g