As far as I know you can't delete the icon any way but deleting the email completely off of your device. The option to hide is the only one available that I know of. That's just my knowledge, though.
Yeah, if you want to get rid of the email address it completely just go into your email setup and delete it. If you just want to get rid of the icon but keep the email, you can only hide it. Sorry for the non-specifics in my previous post.