Here is How you can get user id user information through api Graph
If you did not added your friend you want to know his/her email, Gander , id etc you should Follow the steps.
1. Be sure that you are already logged in in Facebook
2. Go to this page https://developers.facebook.com/tools/explorer/ ,
3. paste the victim/user username Exampler in www.fb.com/jumbohacker (jumbohacker is username)
Hope you like it 🙂