How to hide desktop icons?
Solution 1:
Open a Terminal (with Ctrl+Alt+t) and type the following command to hide icons and disable right-click on the desktop:
gsettings set org.gnome.desktop.background show-desktop-icons false
To restore the default settings:
gsettings set org.gnome.desktop.background show-desktop-icons true
Tested on 12.04, 14.04 and 14.10.
Solution 2:
If you install Ubuntu Tweak, on the tweaks tab, there is section that controls desktop icons, and there is a button at the top to disable.
Note you will have to add the testing ppa as the stable version for 14.10 is not yet out.