Heat 1 tablespoon of the oil in a large saucepan over medium heat. Add the garlic and cook until golden but not browned, about 1 minute.
Add the tomatoes and their juices, red pepper, oregano, sugar, and 1 teaspoon salt. Bring to a boil.
Reduce heat to medium-low. Simmer (crushing the whole tomatoes, if using, with the back of a wooden spoon) until the sauce thickens slightly, about 20 minutes.
Meanwhile, heat the remaining 1 tablespoon oil in a large skillet over medium heat. Cook the sausage until no trace of pink remains. Add to the sauce.
Cook the pasta according to the package directions. Drain and divide among plates. Top each with sauce and ricotta.