Not far from out home is the small harbor of Sai Kung. It is a charming little town with interesting shops and seafood restaurants and a nice ambience.      Fishermen and women tie their boats to the pier and sell the catch of the day to the passersby who call down for what they want. A deal is struck, the fish or octopus or crabs are passed up to the pier in a net at the end of a long pole, and the customer drops the money into the net. Not your average Safeway.