Perhaps the ability to delete your own posts should be included in the forum options
Well, one can - at least in the time frame of ten minutes from first posting…
To do so hit the edit button next to ‘quote’ and in the edit selection hit delete!
After that you have just given the community a +1 post for life 
Your option after this is to pm one of the site admins/moderators and ask them to do so with a good argument why.
Cheers,
Wj
Oops. I didn’t realize I could do that from within edit.