I don't know know what this "remote desktop sharing" is, but a lot of system tray programs work well as services. Use Firedaemon w/it's GUI to make a service for those programs you want to hide, and ...

I now have to support to off-site PCs. I set up VPN connections and firewalls, etc. I plan to admin the PCs with VNC, is there any way to hide the icon from the sys tray? I don't want the users to be ...