GPO option for "Show Desktop Icons"?

Yes, there is an option in GPO.

Do realize that users can still add or create shortcuts or items on their desktops. You can also prohibit this if needed.

If you want to do it using the registry, you can do it in

HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\HideIcons 

you can still deploy this using GPO. You can find this under computer configuration > prefrences > Windows settings and add there the registry you want to create.

I don't know of any GPO policy on its own that will do this, but the registry key to do this is

HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\HideIcons

Set to 1 to hide the icons. If you change the registry directly you'll need to log off and back on to affect the change.