I'm an expat Canadian and dual citizen with all my flying and certificates being US. Back when I was furloughed from a now defunct US carrier, I was looking for awhile into converting to Canadian certificates. Not that hard except that, as is the case in Europe, you have to do written exams for which there is no mickey mouse book of answers to practice/memorize- only books with similar sample questions that are not part of the actual pool. To convert an ATP I would have had to do the Canadian Instrument and ATP written exams, and nuttily, to even apply for those exams one has to get the Canadian medical first. Then last of all one would have to do the instrument/ multi-checkride itself (oral and flight). I think wading through the material for the written is the biggest barrier. There was no formal ground school requirement.
At least, unlike converting to a Euro JAA certificate, there are only two rather than 14 written exams. As far as citizenship goes, for landing a Canadian job- as has been stated, Canada is just like the US in the way it treats foreign job seekers. You don't need citizenship but you do need the right to work i.e. for practical purposes, permanent resident status (Canadian green card).
One difference is that if you are loaded, you can buy Canadian citizenship for around $500,000 as alot of wealthy Hong Kongers did when they were terrified of the mainland takeover. They have since mostly gone back to Hong Kong wheeling in dealing in the mainland wild west. A cheaper way would be to meet and marry a nice Canadian girl. Another cheap way would be to sneak into the country, destroy all documents, and say you are a political refugee from some Third World war zone (it would help to look and sound the part though, tough for a WASP). You will receive generous government handouts for about ten years while the immigration appeals process grinds at a glacial pace, and by that time you will have married a Canadian girl and have Canadian children. Granted, the timeline may be a bit slow for a job with Air Canada.