Preheat oven to 475 degrees. Form dough (as directed in Basic Pizza Dough recipe) in a 9-by-13-inch rimmed baking sheet. Cover with mozzarella in an even layer. Sprinkle with pepper.
Bake until cooked through, crust is golden on edges and bottom, and cheese is golden-brown in spots, about 20 minutes.
Remove from oven. Immediately arrange prosciutto slices in even intervals across pie. Using a metal spatula, slide pie onto a cutting board. Drizzle with oil and sprinkle with salt. Slice into 6 pieces and serve.