When a man winks or blows kisses at a women this is a way that some men flirt......a bit childish and not very effective as many women find it crude but it is a form of flirting.
He is trying to tell the women that he finds her attractive and sexual. Winking is a little more common, but blowing kisses is a sexual action and thus he is displaying his desires for the women. (Wither it be kissing her or more).
Who is he to you?
Are you married or in a relationship?
Is he married or in a relationship?
Has he ever flirted openly with you or talked to you? (If so about what)
but why does he do it to me
He does this to you because he is trying to tell you that he likes you. He is trying to tell you that he wants a relationship with you. If you do not care for his behavior (The winking and kissing displays) you will want to tell him to please stop.
In the end it sounds like he wants you to know he likes you and wants to be in a relationship with you.