Driving & Driving Test Tips: Driving Instructor, speed track, driving instructor

Question
If I am qualified Driving Instructor in UK will I be able to work in Canada/USA

Answer
I don't know for sure, but my guess would be that you would still have to be licensed in North America at a driving school.  

If you are talking about the type of instructor that teaches at high speed track days, there isn't any official licensing method except with certain clubs.  For instance the Audi club has their own school.