Pizza with Swiss Chard, Sausage, and Mozzarella

Preheat oven to 450 degrees F. Lightly grease a baking sheet with 1 tablespoon olive oil; set aside. In a large skillet over medium-high heat, heat remaining 1 tablespoon olive oil. Cook sausage, breaking up with a spoon, until crumbly and lightly browned, 7 to 8 minutes. Transfer to a paper towel-lined plate. Pour all but 1 tablespoon oil from pan. Add garlic and cook over medium-high heat until fragrant, 1 minute. Add chard in two batches, stirring until wilted, 4 minutes. Season with salt and pepper; transfer to a colander to drain. Spread cornmeal onto a clean work surface. Roll out dough into a large oval or rectangle and transfer to a greased baking sheet. Add half the mozzarella, sausage, and Swiss chard, then top with remaining mozzarella and Parmesan. Bake pizza until crust is golden brown and cheese is bubbly, about 15 minutes. Sprinkle with red pepper flakes, season with salt and pepper, and cut into pieces.