What can we use as a wireless switch for a ceiling light?
You can use something like this, if there is room in the fixture:



The switch just mounts on the wall and uses a battery. There is no direct wiring to the fixture.  This company also makes a hand held remote that would work with the socket adapter (instead of or in addition to the switch) as well:



There are also hard wired switching units that fit in a junction box, such as this one



This last one uses the Z-Wave remote system and needs compatible remote controls.

I would not suggest using a fan control box because there is much less venting/air space in a junction box than in a fan housing.