In medium bowl, stir cider, syrup, mustard, paprika, and garlic powder. In 5-6 quart slow cooker, add ham; pour cider mixture over ham. Cover and cook on high 3 hours or low 6 hours or until internal temperature reaches 140 degrees, turning once. Transfer ham to cutting board; loosely tent with aluminum foil and let stand 10 minutes.
Transfer 2 cups cooking liquid to medium saucepot; heat to a boil over medium heat. In small bowl, stir cornstarch and 1 tablespoon cold water; whisk into saucepot and cook 2 minutes or until thickened. Makes about 2 cups.
Carve ham and drizzle with 1/2 cup sauce; serve with remaining 1 1/2 cups sauce.