If using Healthy Italian Breadsticks or Pizza Crust for the crust, wait until the crusts have baked for 20 minutes and then add and arrange all of the toppings (if using a different pizza crust, then follow the directions for that pizza crust).
Spread pesto sauce and then pizza sauce over pizza dough. Sprinkle half of the vegan cheese all over sauce. Arrange tomatoes, and yellow squash or zucchini, over pizza. Scatter onion and bell pepper over vegetables. Sprinkle on the other half of the vegan cheese. Scatter on mushrooms, olives, and sprinkle with red pepper flakes, if desired.
Put the pizza back in the oven to cook for about 10 more minutes.