It is polite to shake hands when you greet someone. In fact there is a cool 3 part handshake that we have learned and the kids give a small curtsey/ bow when greeting an adult as well. They have often been told with a smile, "oh you are learning the Zambian ways, that is good" when they greet the proper way.
Often when you greet and are still speaking with someone it is not at all uncommon for them to continue to hold your hand as they speak to you. Initially this took me off guard a bit and I still notice it but it seems less akward now.
It is also very common for men to hold hands as they are talking or even as they are walking somewhere.
For Americans, this is not at all common. ( for my Zambian friends reading, I will say this almost never happens in America)
I was at the shopping centre this week and tried to discreetly take a picture ( with my phone) so you all could see.
I was walking and 2 construction workers were in front of me walking and holding hands.
To say you would rarely see American men holding hands is true, but to know that the "construction workers" in America would never ever hold hands and walk is even more true.
Then I also saw 2 high school boys standing at the escalator.
For us to think about the groups of men that you would never expect to see holding hands I can surely say it would be construction workers and teenage boys.
It is normal to me now though, and in fact there is a sweetness about it as well. That is how they express their friendship and communicate.
The strange things though is that you see less couples ( man and woman) holding hands in public than you do men and men and women and women. That too is cultural, but not necessarily one of the cultural things that we have embraced. ( I like holding James's hand and he mine!)