Preheat the oven to 400 degrees F. While the rigatoni cooks in salted boiling water, prepare the sauce. In a saucepan heat up the olive oil and saute the eggplant, sun-dried tomatoes, olives, chile peppers, if using, and garlic, for a few minutes. Add the tomato puree and salt. Let the sauce cook for approximately 10 minutes on medium heat. Drain the rigatoni; add the pasta to the saucepan, sprinkle with some Parmigiano and cook for another 30 seconds. Then place 1/2 the rigatoni in a baking dish, adding a layer of 1/2 the mozzarella, 1/2 the scamorza and another sprinkle of Parmigiano cheese over the pasta. Add the remaining rigatoni, and follow with a final layer of all the cheeses. Bake for 20 to 30 minutes or until golden brown.