Preheat oven to 500. Lightly dust a work surface, rolling pin, and a baking sheet with flour. Roll dough out to a 13-inch round and transfer to sheet.
In a small bowl, stir together ricotta, oil and garlic; season with salt and pepper. Spread ricotta mixture on dough, leaving a 1/2-inch border. Top with mozzarella, then Parmesan. Brush oil on edge of dough. Bake until crust is golden and cheese is melted and browned in spots, 12 to 14 minutes.
In a small bowl, toss arugula with oil and season to taste with salt and pepper. Top pizza with arugula and serve.