opening two remote screen sharing on the same client
Just make a New Connection

For the purposes of answering this question, I have connected to two separate Macs - an XServe that I use for Dev purposes and a colleagues MacBook Pro - at the same time.  All my FreeBSD (alternative to Linux)  servers are "headless" and have no GUIs installed - everything is done via command line, so I can't show it connecting to a *nix machine GUI specifically.



To do this, just open a new session in Screen Sharing by clicking "New" on the Screen Sharing menu (top bar) or in Connect to Server (CmdK) and entering vnc://&lt;servername or ip address&gt;

I haven't tested the limit, but I am sure you can add more screens as needed.