I am Cestaro living in london, UK. May dady was born on the Amalfi coast, and we have many relatives still there.
We had always believed that our name was rare, as although there are many Italians in Britain, we are the only ones who bear the name. To find out more info about your Cestaro relatives, you will have to be more specific about the areas in Italy that they left - it will help to find them that side.
Please let meknow if you need further help or onfpormation as my dady or my other realtives may be able to help.