For Special Diets
Halal Food: http://www.discoverhongkong.com/eng/dine-drink/what-to-eat/special-diets/index.jsp
Vegetarian Food (in Chinese): http://www.vegsochk.org/shops/vegilist.htm
Useful App: Openrice
Openrice is a very handy app that has an extensive list of restaurants that you can filter/search by name, location, cuisine, genre, and cost.
Discover food around you:
Web: http://www.openrice.com/en/hongkong/restaurant/index.htm
Play: https://play.google.com/store/apps/details?id=com.openrice.android&hl=en
Itunes: https://itunes.apple.com/hk/app/openrice-kai-fan-la-zui-jia/id310663323?mt=8
Local Foods
Restaurant recommendations coming soon!