Preheat oven to 375°. Cut squash in half lengthwise; scoop out seeds. Place cut side down in baking dish; add water. Cover; bake until the squash is easily pierced with a fork, 20-30 minutes. When cool enough to handle, scoop out squash, separating strands with a fork. Reduce oven temperature to 350°., In a skillet, cook beef, onion, red pepper and garlic until meat is browned and the vegetables are tender, 5-7 minutes.; drain. Add tomatoes, oregano, salt, pepper and squash. Cook and stir until the liquid is absorbed, 1-2 minutes. , Transfer to an ungreased 1-1/2-qt. baking dish. Bake, uncovered, 25 minutes. Sprinkle with the cheese and parsley; let stand a few minutes before serving.