Position an oven rack on the second-lowest level in the oven and place a baking stone on the rack. Position another rack in the upper third of the oven. Preheat the oven to 500°F.
Coat a 12-inch pizza screen or perforated pizza pan with the cooking spray. Remove the dough from the plastic bag and place on a lightly floured work surface. Lightly dust the dough with flour. Using a rolling pin, roll the dough into a 10-inch round without rolling over the edges. Lift the dough and check to make sure the dough isn't sticking to the work surface. Shake the excess flour from the dough.
Toss the dough until it is stretched to a 12-inch circle and place it on the prepared pizza screen or pan. Alternatively, lay the dough on the prepared screen or pan and gently stretch the dough into a 12-inch round.
To top the pizza, brush the dough with 1 tablespoon of the olive oil. Spread the pizza sauce evenly over the dough, leaving a 1/4-inch border. Sprinkle the Parmesan over the top. Scatter the spinach over the top and sprinkle the garlic over the spinach. Cover the spinach with the mozzarella. Using a teaspoon or your fingers, arrange little globs of ricotta evenly over the top. Drizzle the remaining 1 tablespoon olive oil over the top.
Place the pizza in the oven on the upper rack. (Work quickly to slide the pizza into the oven and close the door so the oven temperature doesn't drop too much.) Bake the pizza until the crust is crisp and golden brown, 10 minutes. Using a pizza peel, lift the pizza off the screen or pan and place the crust directly on the baking stone.
Using the peel or wearing thick oven mitts, remove the screen or pan from the oven. Continue baking the pizza until the bottom of the crust is golden brown, about 3 minutes longer. Using the peel, remove the pizza from the oven and transfer to a cutting board. Arrange the tomato slices over the top, if desired. Slice the pizza into wedges and serve immediately.