Wordpress builds in the principle of the author page. The author page is fine and can collect information on the author with a nicename URL. It will not do this with users whom have not written posts.
I want an effective user page that I can theme, www.example.com/user/[user_nicename]. Simple I would have thought, but I cannot find anyway for the code to find the ID of the user which is needed to make this concept work. I cannot find a plugin either. Most provide a profile page for the logged in user only and not for reference of other users.
How can this be done.