Preheat oven to 400 degrees.
Meanwhile, heat olive oil in a large skillet over medium heat. Add onion, tomatillos, and bell pepper to the skillet and cook for 5 minutes.
Add zucchini to the skillet and cook for an additional 3 minutes.
Add garlic, corn, cumin, salt, pepper, and juice from half a lime to the skillet. Cook for an additional 2-3 minutes. Remove from heat and set aside for the moment.
Place tortillas on two baking sheets. Place in the preheated oven for approximately 2 minutes. Flip and cook for an additional minute.
Remove baking sheets from oven. Sprinkle a little cheese on the bottom half of each tortilla, followed by the veggie filling from your skillet, followed by the rest of the cheese. Fold the top part of the tortilla down.
Place the baking sheets with your quesadillas back in the oven and cook for 2-3 minutes, or until cheese is melty and the tortilla feels just slightly crisp. Enjoy as is, or top with a little guacamole!