There are more restaurants in Hong Kong per square foot than anywhere else on earth, so a guide is not so necessary. But just a few words may be useful. The closest shopping mall to CUHK is the New Town Plaza, in Shatin, where an array of restaurants of various types and nationalities, a department store (YATA), and various shops can be found in Tsim Sha Tsui, Ashley Road is a good restaurant street, with 15 or so different places, from Chinese to Japanese to Korean to Southeast Asian to Italian.  For adventurous types, Chungking Mansions, 36-44 Nathan Road, beckons: you will be mobbed by touts as you approach, and just follow any one of them for a good cheap Indian meal. 

(Dining directory of the New Town Plaza: http://www.newtownplaza.com.hk/dining_directory)