How do I start a facebook conversation with a guy who hardly knows me?

[Chris]

You could always open with 'Hello' =)

I realise that isn't a very desirable answer for you, but he might be really flattered! Alternatively you could 'Accidentally click the wrong name', say something that invites a question like "Should I just tell him or am I kidding myself?", make it up from there and eventually you'll be in a conversation =) Sounds a bit odd when written down but it worked for me!

Best wishes, and good luck! x