Everyone thinks the Modern UI in Windows 8.1 means a nearly complete abandonment of the mouse and keyboard for apps however, you might be surprised to learn that there are more than 60 keyboard shortcuts that can be used in the Modern Mail App.

Here is a sampling from the list:

CTRL + R Reply
CTRL + F Forward
CTRL + N New Message
ALT + S Send Message
ALT + I Insert Attachment

You can see the entire list at the Mail Apps support page.

Not bad for a UI that is no good on non-touch devices huh?