You can serve this dish hot or cold. We prefer the crab balls hot, when their exterior is crisp and the meat hot and moist. They also go better with the vinegar dip when hot. If you prefer to serve them cold or at room temperature, delete the dip, or substitute something like mustard and catsup. Preparation: If youre using food processor, crab and pork fat should be cold. Cut pork fat into cubes. Trim and cut scallion into 1" sections, including greens. Using steel blade, place water chestnuts and scallion in bowl; pulse/start to chop vegetables. Add crab meat and pork fat; pulse/start to mince. Add eggs, sherry, salt, corn- starch and minced ginger. Pulse/start 3 or 4 times to blend. Dont overdo it; you dont want a puree. Deep-frying: In wok or deep-fryer, heat oil until bubbles form around a bamboo chopstick held upright in oil. Using teaspoon, form small ball of crab mixture. Test cooking temperature; it should brown and cook through in about 5 minutes; adjust heat if necessary. Proceed with deep-frying about 6 balls at a time; avoid crowding them. Drain on bamboo strainer or towel. If you cant serve them immediately, refry briefly to crisp skin. Avoid overcooking. Vinegar dip: Mix ingredients in a shallow bowl; place on serving platter and surround with crab balls.