They'll still be able to monitor what web sites you
visit. They'll still be able to monitor your network traffic. If they see
any abnormal traffic they're going to start looking closer at what you're
doing. They won't be able to see what's actually on your Linux desktop
screen at that particular second. If they normally remotely view people's
desktops, they usually have a written policy that says trying to get around
the monitoring "can lead to disciplinary action up to and including
termination." If your goal is to avoid monitoring, I wouldn't even go
there. You'll get caught. If your goal is just to learn about Linux using
a Live CD, I'd run it past your local IT guru so you don't get in trouble.