It might be trickier than that. The aluminum rails that the foot pads slide on are sometimes tapped for a threaded rod that goes through the foam. In this type of installation, the whole track actually has to be unscrewed off the end of the threaded rod.
In other types of installations, a threaded rod goes through an untapped hole in the track and receives a nut to secure the track. This makes the track much easier to remove but there is often a nut riding on the outside of the track that you can scrape your leg against.
I have also seen installations in which the tracks had tapped holes and stainless steel threaded rods were screwed into them to hold them on. The ends of the rod were then cut off and the end peened to keep them from unscrewing, which eliminated the need for a nut or screw, but made the tracks a bear to remove.
In another type of installation, the tracks are held on with stainless steel machine screws that go into a tapped solid PVC rod that goes through the foam. This type of installation makes the tracks easy to remove and the machine screw is less obtrusive.
What type of canoe are you talking about and do you know who made the saddle?