All you need is a pair of pliers to pull the staples, a hex key and a spanner to remove the cover and bolts.
A pen to mark out what you want to remove, an electric knife to carve it, an angle grinder with a fine/medium grade sanding pad to smooth out the foam.
A staple gun to refit the cover, refit the two bolts and job done.
Shouldn't take more than 2 hours to do.
Check out this website for some tips
http://www.diymotorcycleseat.com/