In a medium mixing bowl, combine yeast and warm water, let sit until yeast foams, about 5 minutes. Stir in oil and salt. Add flour, 1/2 a cup at a time, mixing with a large spoon, until dough comes away from the side of the bowl and holds together. Sprinkle additional flour onto flat work surface. Turn out dough and knead about 5 minutes, until smooth and springy, add only enough flour to keep dough from sticking to board. Form dough into ball, place in a medium bowl, cover with plastic wrap and place somewhere warm. If you want to freeze some for later, this is the time to place in freezer, then thaw and allow to rise, usually a working day. Let rise until doubled in size, about 2 hours. Preheat oven to 475 degrees. Place dough on a lightly floured work surface, flatten with your hand. Roll dough out from center, form to be about 1/4 inch thick. Sprinkle stone or baking sheet with cornmeal. lay crust on cornmeal. Lay alternating slices of tomato and cheese on top of cu=rust, slightly overlapping each peice. Lightly drizzle with olive oil if desired. Let pizza rest 10 minutes, this makes for crispy crust. Place pizza in oven and bake 20 minutes or until cheese is melting and browning a bit. Sprinkle pizza with basil. 237 calories, 7g total fat, 2 g saturated fat, 0 chol, 31 g carb, 12 g protein, 5 g fiber, 703 mg sodium