I have green board on the bathroom walls, and durarock on the floor and the entire shower. This is a new bathroom I am building. My question was should I put the paper corner bead on the corners which have durarock. These corners are the sides of my shower where my doors are going. If I use corner bead can I just mud it regularly before I tile.

Fiberglass tape. Use thinset mortar to "mud". Let dry, then tile.

Stew

You can use compound- but use the 20 minute type. It sets up harder and will resist moisture better than standard mud.