CILz explains how to do it...LC comes with a tool for removing it cleanly. If you have it installed for all users in the default location, that is to say "/opt/runrev", then go into "livecodecommunity-X.X.X" and launch "./.setup.x86" which will uninstall LC. It will remove all files in the "/opt/runrev/livecodecommunity-X.X.X" as well aw the icon in the menu. That's it.
See http://forums.livecode.com/viewtopic.php?f=20&t=14829 for more