I assume you mean "everything associated with your user-name", as there is nothing of note in your user profile per se.
You can't: the system needs your user name so that the references to any games you have played still exist. After all, the people you have played may be around for a long time yet.
The best you can do is:
Play out and/or resign all your current games
Remove all info from "My Profile settings" (in your case, none)
Set the max games number in "My challenge settings" to zero
Set an invalid email address in "My Personal Details"
Turn off move notifications in "My site settings"
In "My vaccation settings", flag yourself on vacation with the message "Left the site: bye all". Or don't. That last one is up to you.