How to disable the right click functionality on the desktop?

Follow the given steps to disable the right click functionality on desktop:

Click Start button and type regedit in Run option then press Enter for next.

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer

Here in right side panel, right click to create a new DWORD value with the name NoViewContextMenu (it is case sensitive), 
then assign number 1 in value data box.

Now close the registry editor and restart your computer
after any changes to go into effect.

But next time, if you want to enable right click functionality on desktop then 
simply change the value of data box or 
delete the NoViewContextMenu DWORD item.