How to Black Out Remote Screen

I have seen this discussed, sort of, but I cannot find a definitive answer. When I logon to a remote system at work from home, the display for the office system shows me logging on and everyone can see my desktop. The suggested solution was to 'blackout' the session but a) I can't find that option in the '13 client and b) Simply blacking out a screen seems really diodgy to me. Is there a better way to do that or is this secure enough?

Cheers
John