1. Heat olive oil in a skillet over medium heat.
2. Add diced bell pepper, onion, and zucchini. Cook until tender, about 5 minutes.
3. Stir in cumin, chili powder, salt, and black pepper. Cook for another 2 minutes.
4. Remove vegetables from skillet and set aside.
5. Place a tortilla in the skillet, sprinkle with cheese, add cooked vegetables, and top with another tortilla.
6. Cook until the bottom tortilla is golden brown, then flip and cook the other side until golden and cheese is melted.
7. Repeat with remaining tortillas and filling.
8. Cut quesadillas into wedges and serve warm.