There’s a good deal going between Montreal YUL and Hong HKG on Delta Airlines. This fare doesn’t show up on ITA Matrix, but it does both on Kayak.com and google.ca/flights. It’s bookable between September and March, with fairly wide availability. If you’re looking at doing this is a mile run, you can get around 3.6CPM, which is pretty good for a Canadian flight.
Update: Looks like there’s some scattering of dates that work with Toronto YYZ as well.
What the easiest way to find the toronto flights ?
Google flights seems to be the best. Happy hunting!