Heat 1 tablespoon oil in a medium saucepan over medium heat. Add cinnamon and smashed garlic. Cook until fragrant, about 1 minute. Add rice and toss to coat. Add cider and 2 1/2 cups water. Season with salt and pepper. Bring to a boil; reduce heat to low, cover, and cook until rice is tender, 15 to 17 minutes, adding cranberries during the last 10 minutes of cooking.  Meanwhile, heat remaining 2 tablespoons oil in a large skillet over medium heat. Add onions and season with salt and pepper. Cook, stirring occasionally, until onions are tender and beginning to brown, 18 to 20 minutes. Add chopped garlic and cook, stirring, until fragrant, 1 to 2 minutes. Stir in vinegar and parsley. Add scallions and onion mixture to rice and toss to combine.