Make Customizer Load Specific Page

Yes, you can definitely make the customizer load a specific page. You can also set a return page. You can do this with the query strings url & return. You need to pass encoded urls for these to work. So instead of loading http://yoursite.com/wp-admin/customize.php you will want to load http://yoursite.com/wp-admin/customize.php?url=http%3A%2F%2Flocalhost%3A8888%2F%3Fpage_id%3D2

In my example the customizer will load the page with page id = 2.

You can do the same for the return page with the return parameter.

See the wp-admin/customize.php file for more info.