How do I delete my HN account?

Sorry, it's just a matter of the inbox exceeding my capacity to process it quickly.

Maybe try (politely) emailing him once more? He's probably bombarded with lots of emails all the time and might have missed yours.

Also, dang usually doesn't like people deleting accounts (since it goes against the HN philosophy of leaving the website as a permanent record). A more easily accepted request is to change the username to something different, which is not a bad option if you want to erase traces of yourself.

I emailed them now pointing to this thread in case your email was filtered by spam filter or such.

You can't.