Place a pizza stone or heavy baking sheet in oven. Preheat oven to 500° (keep pizza stone or baking sheet in oven as it preheats).
Place the dough in a medium microwave-safe bowl coated with cooking spray. Cover and microwave at MEDIUM (50% power) 45 seconds. Let stand 5 minutes.
Combine 2/3 cup water and porcini in a 2-cup glass measuring cup. Microwave at HIGH 4 minutes or until tender; drain. Coarsely chop porcini.
Heat a large skillet over medium-high heat. Add oil; swirl. Add fresh mushrooms and garlic; sauté 5 minutes. Stir in porcini, pepper, and salt.
Roll dough into a 12 x 8-inch rectangle on a floured surface. Carefully remove pizza stone from oven; arrange dough on pizza stone. Spread pesto over dough, leaving a 1/2-inch border. Sprinkle cheese over pesto; top with mushroom mixture. Bake at 500° for 13 minutes or until crust is browned and crisp. Cut into 8 pieces.