How to Make It
Place rack on lowest position in oven and set a baking sheet on top. Preheat to 500°F. Line a second baking sheet with parchment. Place dough on top, and stretch or roll it into a roughly 9-by-13-inch rectangle, leaving a 1/4-inch area of slightly raised dough around edge.
Spread pesto evenly over dough, leaving edge plain. Scatter zucchini, onion and sun-dried tomato over, then sprinkle with cheeses.
Transfer parchment and pizza to preheated sheet in oven. Bake pizza until crust is lightly browned and cheese has melted, about 10 minutes. Serve, passing around extra Parmesan and pecorino at the table, if desired.