Place zucchini in a large deep skillet and add enough boiling water to cover. Cook for 10 to 12 minutes, then chill quickly under cold water. Cut off stem end of each zucchini and split lengthwise. Starting from wide end of vegetable, scoop out pulp with a spoon,leaving a 1/2 inch thick shell; reserve pulp.
Place shells in a 9x13 baking dish. Preheat oven to 350. In a food processor mince scallions, green peppers, and parsley. Add drained tomatoes (reserve the liquid), reserved zucchini pulp, turkey, spices, and bulgur and process until well mixed. Generously spoon mixture into scooped zucchini shells.
Add enough water to reserved tomato liquid to make 1 cup, stir in a little tomato paste, and pour around the bottom of baking dish. Cover pan with foil and bake for 35 minutes, removing foil every 10 minutes to baste with liquid. Remove foil completely for last 5 minutes of baking. Serve hot with lemon wedges.