Step 1Lightly oil 2 large baking sheets and sprinkle with cornmeal. Cut dough in half. Pat each half into about 12x10-inch rectangle on each baking sheet. Distribute onions and garlic over each, dividing evenly. Drizzle with olive oil. Sprinkle with red pepper flakes, salt and pepper to taste, and poppy seeds.
Step 2Bake on lower oven rack at 450 degrees until golden brown, about 15 to 20 minutes. Cut into squares. Serve hot.