Sauté the Vegetables:
Heat the olive oil in a large skillet over medium heat. Add the diced red bell pepper, yellow bell pepper, onion, and zucchini. Sauté for 5-7 minutes, or until the veggies are softened. Add the minced garlic and cook for another minute until fragrant.

Season the Veggies:
Stir in the ground cumin, chili powder, salt, and pepper. Add the black beans to the skillet and cook for another 2-3 minutes, just until the beans are warmed through. Remove the mixture from the heat.

Assemble the Quesadillas:
Heat a separate non-stick skillet or griddle over medium heat. Place one tortilla in the skillet and sprinkle with about 1/4 cup of shredded cheese. Add a generous scoop of the veggie and black bean mixture on top of the cheese. Add another small handful of cheese on top, then place a second tortilla on top to form a sandwich.

Cook the Quesadilla:
Cook the quesadilla for about 2-3 minutes on each side, pressing gently with a spatula to help the cheese melt and the tortilla crisp up. Flip carefully and cook the second side until golden brown and crispy, and the cheese is fully melted.

Serve:
Remove the quesadilla from the skillet and let it cool for a minute before cutting it into wedges. Serve with your favorite toppings like sour cream, salsa, guacamole, or fresh cilantro.