Preheat oven to 400 degrees F. Line a 12-inch pizza pan with parchment paper. Sprinkle with the 1 tablespoon cornmeal; set pan aside.
Place shredded zucchini in a colander set in the sink; press several times with paper towels to remove excess moisture (you should have 2 cups packed zucchini after draining).
For crust, in a large bowl combine egg, 1 cup of the cheese, the flour, the 1/4 cup cornmeal, the sage, and garlic. Stir in the drained zucchini. Spoon mixture onto the prepared pizza pan. Using your hands, press into an even layer. Drizzle with oil.
Bake for 25 to 30 minutes or until golden. Remove from oven; cool slightly. Using a spatula, loosen crust but do not remove from pan (this keeps the crust from sticking after the final baking).
Top with desired pizza toppings and the remaining 1/2 cup cheese. Bake about 8 minutes more or until toppings are heated through and cheese is melted. To serve, cut into 12 wedges.
Quick Gluten-Free Marinara Sauce
Place tomatoes in a food processor or blender. Cover and process or blend until nearly smooth. Stir in basil; set aside.
In a large skillet heat oil over medium heat. Add garlic; cook and stir until garlic is lightly browned. Stir in tomato mixture, crushed red pepper, salt, and black pepper. Bring to boiling; reduce heat. Simmer, uncovered for 10 minutes. Use on pasta, pizzas, and bruschetta.