Cook pasta as directed on package. Drain, reserving 1/2 cup of the cooking water; cover to keep warm.
Meanwhile, in 12-inch nonstick skillet, cook sausage over medium heat 5 to 7 minutes, stirring occasionally, and breaking into 3/4-inch pieces, or until no longer pink; drain. Set aside.
In 3-quart saucepan, stir cooking sauce, flour, 1/2 teaspoon salt and 1/4 teaspoon pepper with wire whisk until smooth. Cook over medium-high heat 3 to 5 minutes, stirring frequently, or until thick and bubbly. Stir in sausage. Wipe out skillet.
In same skillet, heat oil over medium-high heat. Add arugula and sun-dried tomatoes; cook 2 to 4 minutes, stirring occasionally, or until arugula is wilted. Stir into sausage mixture.
Toss cooked pasta with sausage mixture, adding reserved cooking water 1 tablespoon at a time until sauce is of desired consistency.