Preheat oven to 400 degrees. Cut up the zucchini, onion, and tomatoes, and shred the cheese if not using pre-shredded.
Arrange the naan on two rimmed baking sheets, bubbly side up. Spread each piece of naan bread with 1 tablespoon of pesto, then top each with shredded mozzarella.
Top each naan pizza with zucchini, onion, and tomatoes (overlapping zucchini as necessary), then sprinkle on the shredded Parmesan.
Bake at 400 degrees for 17-18 minutes, or until pizzas are nicely browned. (Switch baking sheets between oven racks halfway through.)
Top pizzas with crushed red pepper to taste, then slice and serve.
Notes
I used a mix of cherry and grape tomatoes from my garden, but either would work nicely. You might also note my pizzas are a little overly browned; I left them in a couple of minutes too long, because my Alexa timer somehow failed me. They were still darn tasty, though!