Cook whole zucchini squash in boiling water to cover 5 minutes; drain.
Slice in half length-wise, scoop our pulp, leaving 1/4-inch shell.
Chop pulp, and set aside.
Place shells in a 12- x 8- x 2-inch baking dish coated with cooking spray; aside.
Coat a medium skillet with cooking spray; place over medium heat until hot.
Add lamb to skillet, and cook until browned, stirring to crumble, drain well in a colander.
Wipe skillet dry with a paper towel, and return lamb to skillet.
Add reserved zucchini pulp, tomatoes, onion, garlic, parsley, salt, pepper, and cinnamon to lamb.
Cook over medium-low heat 10 minutes, stirring frequently.
Remove from heat, and stir in cheese.
Spoon mixture into reserved zucchini shells; bake at 350° for 15 minutes or until thoroughly heated.