Single-User Deletion:

In order to permanently purge a single-user from the “Deleted users” section, execute the following:

Remove-MsolUser –UserPrincipalName

Get-MsolUser -ReturnDeletedUsers | Remove-MsolUser –RemoveFromRecycleBin –Force

This will work with BOTH DirSync’d and non-dirsynched (Users created directly in the Office 365 tenant).

Bulk User Deletion:

If you have multiple users that need to be purged, you can then execute the command below:

Get-MsolUser -MaxResults 30 -ReturnDeletedUsers | Remove-MsolUser –RemoveFromRecycleBin –Force

NOTE:  The –MaxResults parameter is variable, and you can choose a different number other than 30.  This particular command will purge the first 30 deleted users that the command encounters.  You can adjust this lower or higher.  Keep in mind that the higher that you make the number, the longer it will take to run as it is trying to purge/accumulate a larger number of accounts to purge.

Purge External Contacts:

A similar command can be run to purge deleted contacts as well, in case you need to quickly recreate them

Get-MSOLcontact –SearchString “gary” | FL DisplayName, EmailAddress, ObjectID Remove-MSOLContact –ObjectID “ObjectID”

Where “gary” is part of the Display Name for the contact in question.