Check this out: If you’re using Office 365, SharePoint Online will be presenting users with a touch-friendly interface very soon that will work across all supported touch devices.
Read more here:
- OFFICE BLOG: SharePoint Online introduces the Touch Design mobile experience
http://blogs.office.com/b/office365tech/archive/2013/11/19/sharepoint-online-introduces-the-touch-design-mobile-experience.aspx