Q: How do you get rid of email preview pane?

You don't. It's part of the mail program. If having it is a deal breaker then you should look for a different mail program.

In portrait mode you get rid it by tapping the main screen.

Opps, I had it backwards. I should have listened to Skydiver.

I know that's how it is in landscape, afraid I never check my mail in portrait

I had the terms backwards. I thought Kirsten wanted to get rid of the inboxes.