Start charcoal fire or preheat gas grill to medium-high heat.
Combine 2 cups flour, undissolved yeast, sugar and salt in a large bowl. Add very warm water and oil; mix until well blended, about 1 minute. Gradually add enough flour to make a soft dough. Dough should form a ball and will be slightly sticky. Knead** on a floured surface, adding additional flour if necessary, until smooth and elastic but not sticky, about 5 minutes.
Divide dough into 8 portions. Pat or roll dough on a well-floured counter to about 8-inch circles; they do not need to be perfect.
Brush both sides of crust with additional oil. Using hands, lift each crust carefully and place on grill. Cook for 3 to 4 minutes until bottom is lightly browned and top looks set. Using long handled tongs, remove crust from grill, grilled side up, to a platter or baking sheet.
Lightly add sauce and top the grilled side of each pizza crust. Excess sauce or toppings makes the pizza hard to handle. Repeat with remaining pizzas.
Carefully slide each pizza onto the grill. Cook an additional 3 to 4 minutes until bottom of crust is browned and cheese is melted. Remove from grill and serve immediately.
*If you don’t have a thermometer, water should feel very warm to the touch.
**To knead the dough, add just enough flour to the dough and your hand to keep the dough from sticking. Flatten dough and fold it toward you. Using the heels of your hands, push the dough away with a rolling motion. Rotate dough a quarter turn and repeat the ‘fold, push and turn’ steps. Keep kneading dough until becomes smooth and elastic. Use a little more floor if dough becomes too sticky, always working the flour into the ball of dough.
Make Ahead: Dough (but NOT individual crusts) may be made up to 24 hours in advance and stored covered in the refrigerator. Punch down and roll out just before grilling.