Chicken and Vegetable Quesadillas
1 tablespoon chopped fresh cilantro 1 tablespoon olive oil 2 cloves garlic, minced, or more to taste 2 slices sharp Cheddar cheese 4 whole wheat tortillas olive oil cooking spray salt to taste ½ avocado, mashed ½ cup rinsed and drained canned black beans ½ red bell pepper, cut into 1/2-inch squares ½ yellow squash, cut into 1/2-inch cubes ¾ cup diced rotisserie chicken meat