Cut zucchini in half lengthwise and hollow out, leaving shell 1/4" thick. Chop pulp and measure 2 cups. Cook sausage, crumbling meat as it cooks. Add zucchini pulp, onion, garlic to the meat and continue to cook until sausage has lost all pink color. Meanwhile, cook macaroni and drain in colander. Drain fat from sausage and combine with macaroni, tomato, cheddar cheese, parsley, oregano and salt, mixing well. Preheat oven to 350. Brush inside of zucchini halves with olive oil and salt them. Mound the filling in the halves and place in a shallow baking dish. Add about 1/2 cup or more of water, cover with foil and bake for about 45 minutes. Remove from oven and sprinkle with Parmesan cheese. Serves 4.