Preheat oven to 350 degrees. In a large pot, parboil the rigatoni (about 5 minutes in boiling water), drain and set aside.
In the same large pot, saute the onion and garlic in the olive oil until the onions are transucent. Add the beef and seasonwith the cumin, chili powder, salt and pepper. When the meat is browned, add the tomatos. Mix in the crushed red pepper and basil. Add the pasta, ricotta, zucchini and all but 1/4 cup of parmesan. Mix well.
Transfer to a 2 3/4 quart baking dish and evenly distribute the reamaning parmesan on top of the casserole. Bake uncovered for 45 minutes. It is important not to over cook this dish, or the zucchini will become soggy.