Start by preheating your grill to medium heat, around 350°F (175°C). Clean the grates with a grill brush and lightly oil them.

In a large mixing bowl, toss together the diced zucchini, red bell pepper, and red onion with olive oil, salt, pepper, oregano, and basil. Let them sit for a few moments.

Place the seasoned vegetables directly onto the grill. Grill for about 5 to 7 minutes, turning occasionally until tender and showing grill marks.

In a skillet, add a teaspoon of olive oil and minced garlic. Sauté for 1 minute until fragrant, then add spinach and stir until wilted, about 2-3 minutes. Set aside.

On one half of each tortilla, layer grilled veggies, sautéed spinach, halved cherry tomatoes, crumbled feta, and shredded mozzarella cheese. Fold over.

Return quesadillas to the grill. Cook for 3 to 4 minutes per side until golden brown and cheese is melted. Flip gently to avoid burning.

Let quesadillas cool for a minute before slicing into wedges. Serve with hummus or tzatziki for dipping.