In a large bowl, dissolve sugar in warm water. Sprinkle yeast over water and let stand until foamy, about 5 minutes. Stir in 2¼ cups flour, cornmeal, salt, and 2 tablespoons oil. Blend until mixture forms dough.

Knead dough on a floured surface, incorporating as much of remaining ¼ cup flour as necessary to prevent dough from sticking, until smooth and elastic, about 5 minutes.

Place dough in a deep, well oiled bowl, and turn to coat dough with oil. Cover bowl with plastic wrap to allow dough to rise. Leave in a warm place for 1 hour, or until dough doubles in size.

While dough is rising, cook sausages in a heavy skillet over medium-high heat. Add tomatoes, oregano, and salt and pepper to taste. Set aside.

Preheat over to 500°F. Punch down dough and knead 4 times. In an oiled 10½" cast-iron skillet, press dough with oiled fingers until pizza has a 2" edge/crust and is an even thickness on the bottom. Cover skillet loosely with plastic wrap, and place in a warm area for 15 minutes to allow dough to rise.

Sprinkle dough with half of mozzarella cheese. Top cheese with sausage mixture and remaining cheese.

Bake pizza in lower third of an electric oven, or on floor of a gas oven for 15 minutes. Reduce temperature to 400°F and bake about 10 minutes more, or until crust is golden brown.