To make Crust: Combine flour, cornmeal and salt in large bowl. Stir yeast and sugar into warm water in measuring cup; let stand 5 minutes, or until bubbly. Add yeast mixture to flour mixture, and stir to combine. Knead in 1/4 cup oil, and continue kneading 7 minutes, or until dough is elastic and no longer sticky. Transfer dough to greased bowl, cover and let rise 45 minutes. Punch dough down, and let it rise 45 minutes more, or, if making ahead, cover and refrigerate up to 2 days.

To make Topping: Core and seed 3 peppers. Cut each pepper into quarters. Place in blender or food processor with onion, garlic, salt and pepper, and puree until smooth. Transfer to strainer set over bowl, and let drain 30 minutes. Discard juice.

Preheat oven to 500 degrees F, and set rack on lowest level. Lightly grease 2 pizza pans or baking sheets with olive oil.

Core and seed remaining 2 peppers, and slice into thin rings. Press half of dough into 12-inch round on pan. Spread with half of drained pepper puree, and sprinkle with 1 tablespoon dried oregano. Lay half of mozzarella slices on dough, and add half of pepper rings, zucchini and sliced tomatoes. Sprinkle with 1 tablespoon capers. Repeat with remaining dough and topping.

Bake pizzas 10 minutes on lowest rack in oven, or until crust is crisp and brown and cheese is hot and bubbly.