The Ramban explains Yaakov’s kissing Rachel with these words:
???? ???? ???? ???? ???? ?? ??? ???? ???? ???? ???? ?? ??? ????? ?”? ?? ????? ???”? ????? ??? ?? ??? ???? ?? ???? ?? ?? ?????
The first peshat could be interpreted as referring to the fact that she was ????? ?????, but I think it is more likely that both peshatim are getting at the idea that it was not ??? ????.
Either way, it is dangerous to draw inferences for practical halacha from the narratives in Tanach. As with everything else, if you have a legitimate query about shaking hands with people of the opposite gender, ask your Rav.