Preheat a medium skillet over medium heat.

Add olive oil to the skillet and swirl to coat the pan.

Add minced onion, chiles, salt, and chili powder (if using) to the skillet.

Cook for 8-10 minutes, stirring frequently, until the vegetables soften.

Add diced zucchini, corn, minced garlic, and cooked pinto beans (if using) to the skillet.

Cook for about 5 minutes, stirring gently, until zucchini is just tender.

Remove the pan from the heat.

Sprinkle grated cheese over the vegetables and stir until melted.

Season with black pepper and additional salt to taste.

Serve hot, warm, or at room temperature with lime wedges.