(-_-')

actually..    I think you should give him a chance ..    It is probably very hard for him to get from china to canada.. and the canadian citizenship is probably very important for him and his family.
Maybe he was just having so much pressure adapting to the new environment (new to vancouver)?
how old is he ?..  maybe he was a boss back in China, and now you tell him to do stuff, he just couldn't accept that at the moment...?     
He headlocked you, but he didn't beat you up.. he wasn't using a gun or a knife...  i think this problem can be solved verbally between you and him..  just sit down and talk first...   if that doesn't solve the problem....  then seek help from RCMP..  

fighting back and beat the **** outta this guy is only going to satisfy me momentarily and cause him to be in pain for a certain amount of time only...That's not enough...I wanna get back at him with a BAM!

honestly.. I think you are more dangerous than him..