A: The typical process is to hold down the Squares button on the Slate, then quickly tap the power button, which is similar to and effectively performs the Ctrl+Alt+Del sequence.
Another option is to actually disable having to press Ctrl+Alt+Del, which is an easy option on non-domain-joined machines. To do so, use the Computer Configuration\Windows Settings\ Security Settings\ Local Policies\Interactive logon: Do not require CTRL+ALT+DEL.
This can also be set on domain machines using Group Policy and will be the standard in Windows 8.
To see more FAQs, please go to John Savill's FAQs page on Windows IT Pro.