You don't have to be Canadian. There is a section on the Nav Canada website pertaining to recruitment of foreign controllers
http://www.navcanada.ca/NavCanada.as...rs\default.xml
I know here at YVR ACC we work with guys from Australia, UK, Singapore, Lebanon, Russia etc. The more the merrier.
The Nav Canada website currently says they are only recruiting foreign controllers for high traffic tower positions only (Most likely Vancouver, Calgary or Toronto) ... But I know the ACCs are short staffed as well.
KQ