Doesn't seem like anything about it can be done from the iOS or iPhone or Apple's side of things. You can contact Facebook about it, but that's pretty much it.
I wonder how they find the people they have for those recommendations. I've seen them recommend some people that I've actually met before or associated with, yet never exchanged emails, phone numbers, nor any other contact information. We don't even have mutual friends but yet somehow Facebook knows that I know them.
I've looked up people on FB and they pop up as friends you may know. Friends of friends all pop up. I would guess that I would pop up on anyone else's page too. No more lurking sight unseen!