Right after you post it, there are three words in blue down in the left hand side that stay for a while. One is edit one is delete post and the last I can't remember. after deleting,a pop up asks why. I usually put some lame excuse when actually the post was just stupid.
If I really want it gone and my ability to do so has timed out, I click on Report. There's a message box where I type: "Please delete my post." I use that same function if I want it Moved.