Dissolve yeast and sugar in 1 cup warm water in a large bowl; let stand 5 minutes. Lightly spoon flour into dry measuring cups; level with a knife. Add 2 3/4 cups flour and 1 teaspoon salt to yeast mixture, stirring until well blended. Turn dough out onto a floured surface. Knead until smooth and elastic (about 5 minutes); add enough of remaining 1/4 cup flour, 1 tablespoon at a time, to prevent dough from sticking to hands.
Place dough in a large bowl coated with cooking spray, turning to coat top. Cover and let rise in a warm place (85°), free from drafts, 1 hour or until doubled in size.
Preheat oven to 400°.
While dough rises, remove white papery skin from garlic head (do not peel or separate the cloves). Wrap head in foil. Bake at 400° for 40 minutes; cool 10 minutes. Separate cloves; squeeze to extract garlic pulp. Discard skins.
Cover a baking sheet with parchment paper; sprinkle with cornmeal. Place dough on prepared baking sheet. Roll dough into a 15 x 10-inch rectangle. Lightly coat dough with cooking spray. Bake at 400° for 10 minutes or until lightly browned; remove from oven. Combine garlic pulp, tomato, and remaining ingredients in a medium bowl. Spread cheese mixture over crust; bake at 400° for 15 minutes or until lightly browned. Let stand for 10 minutes. Cut into 12 squares.