Sprinkle tomatoes with salt; set aside. On a lightly floured surface, divide dough in half. Roll or press each to 1/4-in. thickness; place each on a greased sheet of foil (about 10 in. square). Brush tops with 1 tablespoon oil.
Carefully invert crusts onto a grill rack, removing foil. Brush tops with remaining oil. Grill, covered, over medium heat until bottom is golden brown, 2-3 minutes. Remove from grill; reduce grill temperature to low.
Top grilled sides of crusts with Parmesan or Asiago cheese, tomatoes, corn, onion and mozzarella cheese. Grill, covered, on low heat until cheese is melted, 4-6 minutes. Sprinkle with spinach and basil.
Health Tip: Fresh mozzarella has about the same calories and fat as part-skim; they are both lighter than a lot of other cheeses like cheddar, Muenster and provolone.