Check out the royal college of physicians and surgeons of Canada website. You'll likely find a good number of answers there. My guess is that you'd have to take ("write" if you're Canadian) and pass some or all of the following exams: MCCQE 1 & 2, specialty board certifications exams. The other thing you may need to look into is that you have an adequate number of years of GME for your specialty and subspecialty.