Bitcointalk does not have a direct option for account deletion, but you can leave a message in the support thread or contact the administration via personal messages to request deletion. You may need to confirm your decision.
Please note that account deletion can be irreversible, so make sure you want to proceed with it.
Where did you get this information from? And did you even read at least the first two comments of the thread to know that you can't delete an account here in this forum, and the admin won't even ask you to reconfirm your decision because such a request won't be granted? The best thing that can be done is to abandon the account and don't post with it. As far as I know, the account deletion option is not available.