Please don't delete posts like that. They need to be deleted from the UI as there is a lot of other data to clean up.
I'm not at my normal machine right now, but you may be able to use some custom JS (or a template modification) to select the delete option by default when the moderation queue page is loaded. You'll need to submit multiple pages of it, but that should be faster than clicking delete on each item.
One way to quickly set the "delete" value on all of the radio buttons is to do the following:
Open your browser's development console (Usually F12)
Go to the "Console" tab
Enter the following and hit enter:
That should "click" automatically each radio button that has a value of "delete". You then just need to click the "Update Moderation Queue" button and repeat. This saves you from having to modify any templates or write any custom JS.