Blend garlic, pepper, 2 tbsp oil, and 1/2 tsp of salt in a medium bowl
Heat remaining 2 tbsp oil in a large frying pan over medium heat. Add leeks and remaining 1/4 tsp salt and cook, stirring often, until softened, about 8 minutes. Add green onions and cook, stirring often, until wilted, about 3 minutes. Stir into bowl of garlic oil.
Stretch each ball of dough into a 12 inch round and place on a lightly oiled sheet of parchment paper. Flip each dough round onto preheated grill and then remove parchment paper. Grill, covered, until dough puffs, about 2 minutes. Transfer rounds to a baking sheet, grilled sides up.
Sprinkle grilled side of each round with 1 cup of cheese, then half of the onion mixture and half of the remaining cheese. Using a wide spatula, transfer pizzas to grill and cook, covered, 1 to 2 minutes. Then pop any large bubbles of dough (this keeps the pizza fairly flat so toppings stay on). Cook until browned and crisp on bottoms, 3 to 5 minutes more. Remove pizzas from grill, sprinkle with chives and enjoy a glass (or 2) of our Grenache Blanc. Enjoy!
