If you are using Windows Vista or higher, and Server 2008R2 or up, you can do it like this:
( Get-WmiObject -Class Win32_UserProfile | Where-Object { $_.LocalPath -eq 'c:\users\user' } ).Delete()
There is a lot of fuss about if the .Delete method exists or not, it is not in the MSDN, however I just did it on a test 2008R2 machine and it worked as expected.