1. What is kink channel?
Kink is a studio specialized into soft BDSM and so on... You can have an overview of channels here:
http://www.videobox.com/channels2. Which site has the best Asian category?
Well to be honest none of the additional channels are really into this niche so I wouldn't subscribe to them just for this. That said the basic account already cover a wide range of niches with a lot of contents, including Asian movies; channels are great if you want exclusive contents from these studios.
3. Do you want a free Brazzers account? The guy who's been paying has been going strong for a good year or so now.
That's nice of you but I'm sure you will find someone here who will have a better use of it, I already have one actually ^^
Hope I helped.