Are you sure the whole site tower is canted or is it just the center post that has been shifted to the side making it look canted? Many aks need the center post shifted a bit to make it shoot straight. They can have the tower canted though as I had an Egyptian one have that problem. With the post shifted all the way to one side, it still wouldn't shoot straight. Personally, as long as I was able to get it to shoot straight by shifting the post, I wouldn't worry about a minor cant in it.
I took my Egyptian one to a gunsmith to correct, but they still didn't fix it 100% but it now shoots straight. I'm not sure the best way to fix the problem myself. If I were set on attempting it though, I'd remove the pins holding on the site base. Try to rotate the site on the barrel (I'm sure a feat in itself as they can be tough to budge). I figure depending on the amount of cant though, the pin holes may need to be re-drilled and oversized pins installed.