My suggestion would be following implementation.

• have a "delete" button in the "..." dropdown. Visible only to the author.
• author clicks on the button
• if there are no sats on the post, then it maybe just shows up confirmation "Are you sure?" dialog, but otherwise deletes the post
• if there are some sats on the post (e.g. 1000), then it would show a dialog with table like

  Post earned:            +1000 sats
  Deletion fee/donation:  -1000 sats 
  (will be donated into daily rewards)
                                 ===
  TOTAL:                      0 sats

• And the sats would be donated to the daily rewards. (effectively reducing the authors balance by 1000 sats)

The reason for donating the sats to rewards is that the person that paid the sats already received their value (because presumably they already read the post). So there's no need to return the money to them. On the other hand removing post with sats is undesirable (we want to keep valuable posts ;)), so the person removing it should lose some sats.

If the author of the post already withdrew their sats from SN, then fair enough - I don't see that as a huge problem. If we would be really strict, the dialog could ask them to deposit 1000 sats to be able to delete the post... but that sounds like a bit too much.

@k00b, @kr fwiw