The first thing to look at is from your own town company, if they have opportunities via partner company in Hong Kong. Look at your home consulate in Hong Kong (see the right section for that). Of course acquaintance is always a solution so that you could get an internship from someone you know directly or from a friend and who works in Hong Kong.

You can find here an organisation which actually organizes summer internship programs to Hong Kong: www.hongkonginternship.com
It is reserved for students though.

You can always go onto website of big companies in Hong Kong like Shell, IBM or HSBC depending on your area and they might offer some internships to Hong Kong as well for a given short term job to be done there.