1 / Make sure you are logged into the Console and see the following screen.

2 / Click on "Destroy".

3 / Click on "Yes, destroy".

4 / You will be automatically logged out, and your VDI will begin destruction. 

*Note: If you log back in too quickly after destroying a VDI, you may see a screen telling you that you don't have a VDI available--don't worry, it just takes a minute for a new one to be assigned to you. Log back out, grab a cup of coffee, stretch, and when you log back in there will be a fresh VDI waiting for you.