$ zfs set sharesmb=name=myshare yourpool/shares/bob
You can set some text description (Windows Explorer shows this text) for the share using this:
$ zfs set "sharesmb=name=myshare,description=My ZFS share" yourpool/shares/bob
To just turn on cifs sharing for a zfs file system without specifying a share name execute a command like the following. Note that the auto-generated names created using this method are usually not user-friendly.