There would be 2 ways to go about it..
1) Create an API script to call DA for each E-Mail, and delete the accounts, one by one, in a loop.
2) If you know you've not setup anything special with the accounts (eg: not used roundcube) and only did basic imap/pop access, then you might have more luck with a shell script to edit:
/etc/virtual/domain.com/passwd
/etc/virtual/domain.com/quota
for each account, and delete the values from there (script would need to parse out the domain)
Also delete this path:
/home/username/imap/domain.com/user
If you did use roundcube or squirrelmail, there might be left-overs in the database... they won't hurt anything, but will take up space.
The left-over data cannot be accessed unless the given account is re-created (contacts lists, webmail settings, etc...)
John
