List of all users?

Is there a way I can find a list of all the users on the computer. I've searched and found nothing about this.

The reason being is that I need to delete a file that exists on every users account in the same folder, but I don't know any users except for the current user and admin.

Also what would be the way to discover just the current user account name, so that I can create a folder based on that name? I just want to be able to get the user name, no user name within a long path or anything like that.

Thanks in advance.