Bring a large pot of lightly salted water to a boil; cook the rotini at a boil until tender yet firm to the bite, about 8 minutes; drain.
Heat oil in a skillet over medium-high heat. Saute sausage in the skillet until nearly cooked through, about 3 minutes. Add bell peppers, onion, and salt; cook about 3 minutes more. Add jalapeno and garlic, stirring constantly. Add tomatoes and cooked pasta; cook and stir until heated through, about 5 minutes more.