How do I shut down a workstation via Remote Desktop?

depending on the setup of your windows try the 2 solutions:

Ctrl+Alt+End This should be the same as Ctrl+Alt+Del and consequently takes you to a dialog where you can do various system-type things, among them logging off and shutting down.

Another trick is to click on the desktop and press Alt+F4. This will call up the shutdown dialog, where you get the usual shutdown options like “Shut down”, “Shut down without installing updates”, “Restart”, “Stand by”, and “Hibernate”.