How to Send Ctrl + Alt + Del through Remote Desktop?

When you are connected to a remote computer, pressing the CTRL+ALT+DEL combination of keys causes the command to be executed locally on your computer.  How can you send a CTRL+ALT+DEL to a remote machine through Remote Desktop?

In remote desktop, bring up the on-screen keyboard (Start > Run, type osk.exe), then hold CTRL+ALT on the keyboard and click DEL on the OSK.

This should work for any number of nested RDPs.