Spray 4- to 5-quart slow cooker with cooking spray. Place carrots and onions in slow cooker. Top with chicken thighs. Sprinkle with cinnamon, salt, pepper and garlic; top with tomatoes. Cover; cook on Low heat setting 7 to 9 hours or until vegetables are tender and chicken pulls apart easily with a fork.
Remove chicken with slotted spoon; cover to keep warm. Stir tomato paste, lemon peel and oregano into liquid in slow cooker. Cover; cook about 15 minutes longer or until thickened and hot. Meanwhile, remove chicken from bones. Stir chicken into mixture in slow cooker, breaking up larger pieces.
To serve, spoon stew in shallow bowls, and top with parsley.