Preheat oven to 375 degrees F. Line a 15X10X1 inch baking pan with foil; set aside. Cut off and discard tips of chicken wings. Cut wings at joints to make two pieces. Arrange wing pieces in a single layer in the prepared pan. Bake for 20 minutes.
In a 3 1/2 to 4-quart slow cooker combine plum sauce, soy sauce, sherry, butter and ginger. Add chicken pieces, stirring to coat with sauce.
Cover and cook on low heat setting for 3 to 4 hours or on high heat setting for 1 1/2 to 2 hours. Serve in the slow cooker on low heat setting, or transfer to a serving dish. Sprinkle with cilantro and sesame seeds just before serving. NOTE: sesame seeds can be toasted in a dry pan on medium low heat, stirring constantly until lightly browned; remove from pan.