Combine rapid-rise yeast, warm water and sugar in a small bowl and let stand 5 minutes.
Stir together 2 cups flour and next 3 ingredients in a large bowl; stir in yeast mixture and 2 tablespoons oil until well blended (dough will be sticky). Turn dough out onto a well-floured surface and knead until smooth and elastic (about 3 to 5 minutes). Place in a well-greased bowl, turning to grease top. Cover with plastic wrap and let stand 15 minutes.
Sprinkle cornmeal onto well greased baking sheet. Place dough on baking sheet and roll into a 12-inch square (I usually roll it a little larger), sprinkling with flour as needed to prevent sticking (about 1 tablespoon). Cover with plastic wrap and let rise in warm place (85 degrees), free from drafts for 45 minutes.
Preheat oven 400 degrees. Brush dough with balsamic vinegar. Gentilly press end of a wooden spoon into top of dough, forming indentions. Top with tomatoes, garlic and cheese. Sprinkle with salt and pepper. Drizzle with remaining 1 tablespoon oil.
Bake 400 degrees for 20 minutes or until golden and cheese is melted. Cool 5 minutes and cut into squares.