Bring 6 quarts water to a boil and add 2 tablespoons salt.
In a 12 inch to 14 inch saute pan, heat oil and onion over medium heat until just softened, about five to seven minutes. Add crumbled sausage and cook until red is gone. Drain grease from pan and add tomato sauce and kale. Cover pan and simmer for 15 minutes. Meanwhile, cook pasta according to package instructions until just "al dente" and drain. Remove lid from pan and add hot pasta. Toss to mix well and serve immediately. Drizzle with some "new oil" or best quality tableside.
Recipe Courtesy of Mario Batali