How to limit access for some special user to a single (Views) page?
Not sure if it is the "best" approach, but for sure a "possible" approach for this would be to use the Rules module for this. All you'd have to do is to create a (rather basic) rule like so:


Rules Event: Drupal is initializing.
Rules Conditions (both must be true): 


Check if the user's Id (uid) or user's name matches your "special user".
If the URL being accessed (= "site:current-page:url") does NOT match with the URL of your  "single (Views) page"

Rules Action: Perform a redirect to your "single (Views) page".


Done ...

Happy Rules-ing!

Note: Obviously, this rule only takes care of what that special user is allowed to use as URLs (while logged in). If that user does not login (yet) or logs out again, then anything an anonymous user is allowed to navigate to will also be available to this not-yet-logged-in-user. For whatever that is not allowed as an anonymous user, you must ensure that the permissions for anonymous users are set to deny such access.