Cook penne according to package directions in lightly-salted water. When it is done, drain it, reserving 8 cups of the pasta cooking water. Do not rinse it. While the pasta is cooking, heat the olive oil in a large pan over medium-high heat. Remove sausage from its casing in small olive-sized pieces and add the pieces to the heated oil. Cook the sausage, stirring occasionally, allowing it to brown and crisp. While the sausage is browning, drain and rinse the canned beans and remove stems from the kale and roughly chop it. When the sausage is cooked through, add the diced tomatoes with its juice, and bring to a boil. Add the beans, kale and reserved pasta water. Return to a boil and add the cooked penne. Toss the pasta until completely coated with the sauce and the beans, tomato and kale are evenly distributed. Serve immediately.