Setting the password initially for root on a Unix system:
/path/to/mysql/bin/mysqladmin -u root password 'thepasswd'
Deleting root ... dont. In fact, I would recommend actually never using root either. Root is the GOD account, and should only be used if 100% necessary.
What I do is set my root password and then store that information in a safe place (company vault). I then create an administrator account that has the ability to create and drop databases. I then create administrator accounts for each database that has the ability to create and drop tables in that database.
To add new users, I use the mysql_setpermission script.
/path/to/mysql/bin/mysql_setpermission -u dbadmin -p
Then follow the script to add new users/databases/permissions