Crime gangs composed of recent Asian immigrants are on the increase along the east shore of San Francisco Bay, and police in Oakland and other communities said they are concerned that they might unite to form a new sort of organized crime along the lines of the international Wah Ching and United Bamboo gangs. Oakland Police Sgt. Ignatius Chinn, who has arrested 12 Vietnamese and Chinese gang members in the last several months, said the gangs are involved in robbery, extortion, burglary, drugs and prostitution. But Lai Luu, executive director of the Eastbay Vietnamese Assn., said the deeper problem is the immigrants' troubles in assimilating into the new culture. Many of the younger immigrants, he said, look to gangs and other peer groups "to prove they are good."