Preheat the oven to 400°F.
Place the bell peppers, cut side up on a baking sheet pan and spray with cooking spray; set aside.
In a large skillet over medium heat, heat the canola oil, and cook the onion until it softens, about 5 minutes.
Add the ground beef and all the taco seasoning (chili powder, cumin, salt, black pepper, garlic powder, onion powder and Mexican oregano) and cook until browned. Stir in the salsa.
Spoon the taco mixture into the prepared bell peppers, filling them to the top. Top with cheese and bake in the preheated oven until the cheese is melted and the peppers are crisp-tender, about 15 minutes.
Top the peppers with toppings of choice and enjoy!