My understanding is that you do not actually have to make an application. What you need to do is cut ties from Canada including such things as not renewing a drivers license... not maintaining a home in Canada (you can own a property but you must rent it out or be seen to be trying to rent it out -- if you leave it empty that is a problem) --- you definitely should not use free health care if you go to Canada ...
A trust lawyer for HSBC and Weir & Associates in Hong Kong both explained to me that declaring non residency will not matter if you are still determined to have close ties (as above) -- the fewer you have the better.
If uncertain I suggest you contact
shane@hongkonglaw.com 2526 1767