In a medium bowl combine all the salsa ingredients. Toss to combine.
Heat the canola oil in a small nonstick skillet over medium heat. Cook the red pepper and garlic until soft, about 3 minutes. Add the chili powder, salt, and pepper. Cook, stirring frequently, for 30 seconds more. Set aside to cool.
Combine ground meat and pepper mixture. Shape into 4 even patties, about 1/2-inch thick. Lightly coat both sides of burgers with cooking spray.
Heat grill to medium. Grill to desired doneness, about 5 minutes per side for medium (160°F), adding the cheese during the final 2 minutes of grilling. Serve the burgers on buns, topped with avocado, if using, and salsa.