This used to be so easy.
Two options I know of for restarting the server (Win8 or WS2012) in a remote session.
1) Get to the desktop and then use Alt + F4 to get this:
Make sure you minimize anything else running on the desktop, or you’ll have to shut down each app individually, possibly muttering like a grizzled old man trying not to step on any of his cats on the way to the bathroom.
2) The other thing you can do is a the “shutdown /i” command from an admin CMD prompt.