1. Weigh or lightly spoon flour into dry measuring cups and spoons; level with a knife. Combine flour, 3/4 cup warm water, thyme, oregano, and garlic in the bowl of a stand mixer with dough hook attached; mix until combined. Cover and let stand for 20 minutes.
2. Dissolve yeast in the remaining 1/4 cup warm water in a small bowl; let stand 5 minutes or until bubbly. Add yeast mixture and salt to flour mixture; beat at low speed 5 minutes or until a soft dough forms. Place dough in a large bowl coated with cooking spray; cover dough with plastic wrap coated with cooking spray. Refrigerate 24 hours.
3. Remove the dough from refrigerator. Let stand, covered, for 1 hour or until the dough comes to room temperature. Punch dough down. Divide dough into 4 equal portions. Press each portion into a 7-inch circle on a baking sheet sprinkled with cornmeal. Cover loosely with plastic wrap.
4. Preheat grill to medium-high heat.
5. Place pizza dough rounds, cornmeal side up, on grill rack coated with cooking spray, and grill for 3 minutes or until blistered. Turn dough over; grill for 3 minutes. Remove from grill.
6. Sprinkle about 5 tablespoons fontina over each pizza. Top evenly with prosciutto and pepper. Combine oil and lemon juice in a bowl; add arugula, and toss gently. Divide arugula mixture evenly among pizzas. Serve immediately with lemon wedges.