I would hazard to say that CFL teams use predominantly a spread offence. The following is a rather simplistic analysis, and I'm sure others will pick it apart. But the ensuing discussion should provide many insights.
Because of only three downs, there is a higher focus on the pass. As mentioned earlier, QBs are pretty much always in the shotgun, under centre only on short yardage. Teams very seldom use two backs in the backfield, and often the single running back ends up in motion before the snap, resulting in six receivers heading out on routes, four of whom could be hitting the line at full speed at the snap. The rest of the time, the RB often ends up pass blocking, and some teams (Ticats in particular) seem to value pass blocking more that running ability. Hot reads are the standard. The best receivers are often the slotbacks, who come out of the backfield in motion and run their routes mostly in the middle of the field. Because of the distance for throws, the wide side receiver is usually the weakest receiver, and doesn't see the ball as much as the others.
Teams do still run the ball, some more than others, and some teams use the sweep as much as run up the middle.
On short yardage (under a yard), teams almost always go with a QB sneak, which is quite effective, because the defence has to be a yard off the ball before the snap.