G-Mail recently made some changes I'm not happy with. Is there a way to delete g-mail from my inbox without opening it?
swipe the message to the left or right and it will be deleted.
However, the default action is to "archive" it. To set it to delete, tap the lower left menu button and choose settings then general settings. Next tap on Archive and Delete actions and choose Show Delete Only. Next, go back into the general settings menu and make sure that the box for Swipe and Delete is checked.
From this point on you can easily delete your messages by swiping them to the left or right.