1. Preheat oven to 475°. Sprinkle baking sheet with cornmeal.
2. In food processor, blend ricotta, garlic, salt, and pepper until smooth. Add mozzarella and arugula. Pulse to combine.
3. On lightly floured surface, roll pizza dough into a 14-inch circle; transfer to baking sheet. Spread ricotta mixture on top, leaving a 1-inch border. Top with tomatoes and drizzle with oil. Bake 15 to 16 minutes, until the crust is golden.