Do a graph search likes this: "People who like [your fanpage's name]". You will all the result.
Then create shortcut on your browser with this javascripts code, it will click on the View more link and scrolling until all result are shown in the page:
javascript: i = 0;minutes = 30;counter = minutes * 60;function repeatScroll() {
if (i < counter) {window.scrollTo(0, document.body.scrollHeight);i++;}
setTimeout(repeatScroll, 1000);}repeatScroll();
After that, create other shortcut and run this js code to retrieve all UID from the search result:
javascript:var txt="";e=document.getElementsByClassName("FriendRequestOutgoing");
for(var i=0; i<e.length; i++) {v=e[i].getAttribute("data-profileid");
if(v) txt+=v+"\n"}document.body.innerHTML="<textarea>"+txt+"</textarea>";
A textarea box will appear in the screen with all uid inside. Just copy it to your notepad and import into your Custom Audience in Facebook Ad Manager.
I created and use this code everyday to get all UID with criterial I need.
You can launch any graph search you want.
This is homemade code, so using it without your own responsibility :)
Enjoy them.