Which Worksman trike? They make a number of them. The most common is the 20 inch Trifecta or Port-o-Trike, and that's what I have (three of them at present.) I can only speak on this one.
Unless there's been some modification, on the Trifecta, you simply take the nut off the axle and the wheel slides right off. The left wheel is hardly ever a problem. The right, or drive side wheel might give you only the teeniest bit of grief unless it's been welded or something.
On the older Trifectas, the drive axle has a collar that has three prongs or studs that match up to the three holes in the flange of the hub. This is simply a matter of three studs mating to three holes - there are no screws or fasteners, they should pull straight out with no problem. If they bind up, then something has been changed or welded or there is a gob of dirt between the axle and wheel bearing. Otherwise, the wheel just pulls off once you take off the nut.flange
On the newer ones - and this could still mean as old as the late 70s or 80s, I'm not sure when it changed - the hub flange will still have three holes but they no longer serve a purpose. The hub and axle have a key way, and of course there is a key in the key way to keep the drive wheel mated to the axle. Once you've taken off the nut, look in the space between the inner side of the hub and the frame to make sure that little key has come free of the key way in the axle. It should fall right out as you gently rotate and pull the hub away from the frame. If it doesn't, then there's a mod or a gob of dirt binding things up.
Worksman trikes are pretty simple. Take the nut off the axle, take the weight off the rear axle assembly, give it a little wiggle, and pull the wheel off. If it takes any more effort than that, start looking for the cobbled up spot weld or gob of epoxy some nimrod used to fix it. If it's not that simple, then somebody did a jury-rigged repair that has become a problem.