Secure RJ-45 jack?

I work in several schools as basic on-site tech support. At one school (a middle school), students have figured out how to unplug out wireless access points from their jacks. Is there some standard of cable or plug that could be screwed into place to prevent easy removal?

You need a Plug Lock-in Device from Panduit. We use them on MPLS and PRI circuits in a shared telco closet in our building to keep techs from other telco's or over-zealous admins from unplugging them and taking our whole office offline. Keep in mind you need adequate clearance around the plug... I found that they don't work to well on my Ruckus wireless AP's because the plug is receded into the device slightly. I don't know what AP's you have but hopefully it will work for you.

Totally not a shopping recommendation, but you could probably do with an external enclosure combined with a strange bolt to keep their grubby little hands off the equipment.

You could just clip a little bit off the end of the tab that holds the plug in the socket. This means they won't be able to unclip the tab to pull it out, but you can still get it out with a flat head screwdriver or similar.

It's what we do here on some things that are accessible to them.