Divide dough into 2 pieces and roll each into 10" circle. Place each on a sheet of foil and brush both sides with oil.
Heat grill to medium and oil grill grate. Use foil to help flip dough onto grill. Grill 2 minutes or until dough is set and grill marks appear. Turn and grill an additional 2 minutes. Grill onion and tomatoes, turning every 2-3 minutes, until browned and softened. Remove and let cool, then thinly slice tomatoes and coarsely chop onion.
Remove crusts from grill and top with tomatoes, bacon and onions. Sprinkle cheese over toppings and grill pizzas, covered, until crusts are crisp and cheese has melted, about 5 minutes.