I want to customize the wordpress dashboard left-side menu. I want to remove the sub-menus by hovering, instead I want to show them in the menu without hovering. For example when we hover mouse on the ‘Pages’, the submenu with ‘All pages’ and ‘Add new’ appears. I would like to show these options in menu without hovering it.
I’ll appreciate any help or any hint to get started with.

You can already get this functionality by clicking on “Pages”, instead of hovering
If you want the menu options pre-expanded, this plugin will work as well: http://wordpress.org/extend/plugins/expanded-admin-menus/