How to Make It
Light a grill, preferably using hardwood charcoal. Set the grill grate 3 to 4 inches above the coals. In a medium bowl, toss the Fontina with the Pecorino Romano cheese.
Divide the pizza dough into 6 equal pieces; work with 1 piece at a time and keep the rest covered with a towel. On 3 lightly oiled baking sheets, flatten and stretch the dough with your hands to form six 8-inch rounds with 1/16 inch thick; do not make a lip and don't stretch the dough so thinly that it tears. Brush the rounds with olive oil.
When the grill is hot, working in batches if necessary, gently drape the pizza dough over the hot grate and cook until it puffs slightly, the underside firms up and grill marks appear, about 1 minute. Rotate the dough once and cook for 30 seconds.
Brush the top of the pizza rounds with oil and flip them over using tongs. Scatter one-sixth of the garlic and cheese over each pizza, followed by 3 heaping tablespoons of chopped tomatoes. Then drizzle each pizza with 1/2 tablespoon of olive oil.
Slide the pizzas near the hot coals but not directly over them. Using tongs, rotate the pizzas frequently, checking often to make sure that the undersides are not charring. The pizzas are done when the cheese is melted and the tomatoes are hot, 3 to 4 minutes. Scatter one-sixth of the basil and prosciutto over each pizza and serve hot off the grill.