Use a different template file if use is on a mobile device
To do this you need to setup some method that will detect whether the use is coming from a mobile device and than add a function in your template.php file to switch to your mobile template.

For the mobile detection, there are a number of modules available for this but for this specific use case, I would recommend Mobile Switch because it provides a specific variable you can use for testing in your theme (others like Mobile Tools might as well, this is just one I've used before). From documentation: 

Development with Mobile Switch.

The module provides four system variables:

1. mobile_switch_ismobiledevice
2. mobile_switch_istablet
3. mobile_switch_ismobiletheme
4. theme_mobile


From here, you just need to add a template suggestion to your theme through the preprocess_page function using this variable, ex:

function YOURTHEME_preprocess_page(&amp;$variables) {

  global $mobile_switch_ismobiledevice;

  if ((request_path() == 'YOUR_PATH') &amp;&amp; $mobile_switch_ismobiledevice) {
    $variables['template_file'] = 'mobile-YOURTEMPLATE';
  }

}


This method assumes you want to specifically switch between two template files, if you would prefer to use a separate mobile theme, than the Mobile Switch or Mobile Tools module have configuration options to help you do this.