In the mail app, is there a way to both delete mail messages without having to view them first and also to empty the trash folder working viewing the message again?
Yes, I believe on the top, theres a button called "Edit". Push it, and little red circles with a dash comes up, push the circle and a delete confirm message appears. Click on that, and your good to go.
Or, just swipe that message to the right, and the delete message comes up and push it.