I have done Off Road Showas without any special tools, although some say the Harley 39mm Showas require one for dissassembly.
Loosen both the compression and rebound screws, then loosen top cap while still in triple clamps. Remove fork leg from bike and finish removing top cap from fork leg. Now you will have to seperate top cap from damping cartridge so you will need to push the spring down and use something to hold the cartridge from spinning while you use a ratchet and socket to spin top cap off. Then take a small air impact wrench and buzz out the cartridge retainer bolt on the bottom of the fork leg to free the cartridge from the lower.
Of course u still have a few seals to remove and some clips in the seal area to allow disassembly. This is all from what I have read and can see from parts explosions as nobody here seems to have done them on their own.
Use that link for parts micro fiche details.