In a bowl combine hoisin sauce, brown sugar, soy sauce, tomato paste, sherry, garlic, hot pepper sauce, and five-spice powder. Place ribs in a 3-1/2- or 4-quart slow cooker. Pour hoisin sauce mixture over ribs, tossing to coat.
Cover and cook on low-heat setting for 8 hours or on high-heat setting for 4 hours. Using tongs, transfer ribs to a platter. Cover with foil to keep warm.
Transfer cooking liquid to a small saucepan. Skim off fat. Bring to boiling; reduce heat. Simmer for 15 to 18 minutes or until liquid is reduced to 1 cup. Return ribs to slow cooker, add reduced liquid and toss to coat. Keep warm, covered, on warm setting or low-heat setting for up to 1 hour.
Sprinkle ribs with chives. If desired, serve with hot cooked Chinese noodles.