I think I see the blushing smiley emoticon differently to most people, I just use it as a standard smile, so maybe I have been unintentionally flirting with guys for ages ....oh no, girls too! :-0
Is it this one that you mean? Top row, second from left?
Anyway, to answer your question, if he has started to use it recently and hasn't in the past, and as you say, uses it loads, then I am sure that means he likes you a lot.Has he started to say anything to make you think he wants to be with you? I think if you like him too you could maybe start giving him some compliments and see what happens. Hopefully he will tell you he wants to be with you then.
Guys sometimes need a little push from us before they say too much in case we (or worst still, their mates) laugh at them. He sounds like a good one though; I don't like the ones who are too up front and full of themselves.
He definitely deserves a chance so have a little flirt :-)