How can I disable or remove a ceiling fan wall switch?
Yes. Assuming this isn't a 3-way or 4-way switch, all the switch does is connect all the stuff wired into it (excluding the ground conductor, of course). If you want it on all the time, just take the stuff that was attached to the switch and bond it together with wire nuts. Remove the switch and replace the switch plate with a blank wallplate.

For a no-wiring-required solution, you can also buy a switch lock like this: 

That is held in place by the screw that holds your cover plate, and just mechanically prevents the switch from being moved. If you think the switch might be useful in the future, this is a little easier to reverse.