I would create a class to encapsulate it - you could call it "Map" if you wanted.
Actually breaking it into it's constituent parts is simple:
string a = "NAME#####SURNAME####TEL#######ADDRESS######SSN#########WHATEVER#####";
string[] parts = a.Split(new char[] {'#'}, StringSplitOptions.RemoveEmptyEntries);
You can then define constants to access each part by it's index into the parts array.