Are you looking for English idioms or Chinese ones? There's a Swindon by the Ferry Pier that has such books on English idioms, a bigger one in Admiralty's Pacific Centre, and an even bigger one on Tsim Sha Tsui side, two blocks east of the giant Ocean mall, one block west of Nathan Road. If I were you, though, I'd try to stay away from translated idioms, they don't make sense in both languages. Think of this Chinese one: "Don't move, or my gun will have no eyes!"
Student or Learner