Spray an unheated large skillet with no-stick spray.
Heat the skillet over medium heat.
Add the onions.
Cook and stir for 4 minutes.
Stir in the tomatoes, parsley, oregano, marjoram and pepper.
Cook about 2 minutes or until heated through, stirring occasionally.
Stir in the zucchini.
Cover and cook for 4 to 5 minutes more or until the zucchini is crisp-tender.
Transfer the mixture to a serving dish.
Sprinkle the cheese over the top.