Is the blushing smiley emoticon an indication of flirting, or embarrassment, what does it mean, this guys uses it every single time when he msgs me?

The blushing smiley face, in my opinion, is just a standard friendly smile. Is it the blushing emoticon in the first row of the image below that you are referring to?

I use the one in the middle of the top row to message anyone I want to send a smile to - that includes friends of both genders.

I'm not saying this guy is not interested in you, and maybe he sees it in a different way to me.  I just know that if someone sent it to me, I wouldn't think anything of it - maybe I am missing out on some flirting :-)

I think some of them are actually quite sinister, take for instance, the one on the bottom row third from right!

Some people don't like emoticons, but I think they brighten up the text message and therefore my day.

If you are interested in this guy maybe send him the kiss emoticon and see how he responds, you could always claim it was a mistake if it goes wrong...