I searched the internet the whole day for this, and came to the conclusion that there is no way to get a user's full friend list since API 2.0 (correct me if I am wrong).
What I want to do is, given the app user and another facebook user, generate a report about their "second level" mutual friends. That is - (friends of mine) who are friends with (a friend of his). Illustration: 
Is this kind of thing possible after facebook's restriction since API 2.0 in any platform (Different SDKs, Facebook's Graph API, etc)?
Many Thanks.
This would be the API: https://developers.facebook.com/docs/graph-api/reference/user-context/all_mutual_friends
There is no way to get friends (or users in general) who did not authorize your App. Every list you get will only include users who authorized your App.