TOMATO SAUCE: Purée tomatoes in a food processor with garlic, salt, red pepper flakes, and sugar. Set aside.
PIZZA: Heat oven to 500°F. Heat a medium skillet over medium heat. Remove sausage from casing, crumble, and sauté about 5 minutes, or until lightly browned.
Flour an overturned baking sheet. Stretch pizza dough to a 13-by-9-inch rectangle, and transfer to baking sheet.
Top dough with tomato sauce, mozzarella, sausage, pepperonicini, and goat cheese.
Bake 10 to 15 minutes, or until the bottom of crust is crisp and brown. Transfer to a cutting board and let cool 5 minutes before serving.