Bending brakes is not a good idea because you have to keep bending them as the pads wear parallel to the rim. Eventually when you replace with new pads, you end up with a 1/4" gap at the rear of the new ones. Bending them back will certainly snap them.

Your brakes SHOULD have adjustment for toe. The part that holds the brake-shoe post should be able to swivel when the rear nut is loosened. A lot of cantilevers have a conical rear to allow for swivel.

Worse case scenario, just bevel the rear of the pads yourself. Take the pads off and touch on a grinder for 1-2 seconds, or use a spinning disc on the shoes while they're mounted.