Hong Kong doesn't die down at night. The best time to go out to eat (and get a view) is for dinner.  There are many options for you to consider.

You can go to Jumbo Restaurant, the famous floating seafood restrauant, located in Aberdeen.  

You can dine at one of the spectacular hotels which have a view to go with it. The Excelsior Hotel in Causeway Bay has a view of the Hong Kong Harbour. The Ritz Carlton, which as recently reopened at the new International Commerce Centre (ICC) building, offering a meal or drinks from over 118 floors above street level, while enjoying the lights of Victoria Harbour..

You can even dine at one of the cheaper places such as the McDonalds located in the "World Trade Center" in Causeway Bay which has an excellent view of the Hong Kong Harbor.

Also in the World Trade Center there is also The Spaghetti House which will give you the same view.

The Peak (Victoria Peak) offers some breath taking views while dining, and there are several options to that. Try the restaurants and cafe's in the Peak Tower itself or Peak Galleria.  CafeDeco, in particular, offering fantastic views of the Kowloon skyline at nighttime.