Preheat oven to 350 degrees. Grease or spray 13x9 baking dish
Cut the zucchini in half lengthwise. With a spoon, scoop out seeds. Chop and reserve about 3/4 of the seeds for the stuffing. In a medium bowl, mix together ground beef, sausage, chopped onions, bread crumbs, eggs and the reserve zucchini seeds. Place the meat mixture equally into all the zucchini halves; mixture should be piled up over the top. Place the filled zucchini halves into the prepared baking dish.
In a bowl, stir together the crushed tomatoes, tomato soup and water. Spoon the tomato mixture over the filled zucchini, liberally. Bake in the preheated oven for approximately 45 minuets. You may want to place foil or a cookie sheet underneath the baking dish because it tends to boil over and splash.