How can I disable the phpMyAdmin login page?

In your config.inc.php file change:

$cfg['Servers'][$i]['auth_type']    = 'config';  

and add

$cfg['Servers'][$i]['user']         = 'root';  
$cfg['Servers'][$i]['password']     = 'password';

In centos, locate the file in directory /etc/httpd/conf.d/phpmyadmin.conf/ and uncomment these lines to only give access on the local system to phpmyadmin, and leave the users from outside with no access to phpmyadmin

<Directory "/usr/share/phpmyadmin">
  Order Deny,Allow
  Deny from all
  Allow from 127.0.0.1
</Directory>

Hope this be helpfull

You can disable phpMyAdmin by disabling the module configuration.

sudo a2disconf phpmyadmin.conf
sudo /etc/init.d/apache2 restart

Enable it with

sudo a2enconf phpmyadmin.conf
sudo /etc/init.d/apache2 restart