- In a large pot of salted boiling water, cook the pasta al dente. Drain and oil lightly. Set aside.
- Over a work surface, with your hands, squeeze the sausage meat out of the casing, breaking it into about 2 tsp pieces.
- In large non-stick skillet, brown the sausage pieces, cherry tomatoes and garlic in the oil for about 2 minutes. Add the pepper and hot pepper flakes. Continue cooking for 6 to 8 minutes or until the tomatoes have burst.
- Add the zucchini and green onions and cook for about 5 minutes, stirring frequently, or until the zucchini are tender and the meatballs are cooked through. Season with salt. Add the pasta and toss well.
- Divide among four serving plates. Sprinkle with the Parmesan cheese and top with a piece of mozzarella.