De acordo com o aplicativo da Wikipedia para Windows 8 e tablets Windows RT do blog da Wikimedia:
The app integrates with Windows 8′s global search widget, which can be used both to search while in the application and to launch the app — select Wikipedia from the search providers when doing any search and you’ll pop over to us.
On a laptop or desktop device with a keyboard, you can simply start typing to begin a search, just like on Windows’ Start screen.
Para abrir a pesquisa "charme" usando um mouse (de Uma introdução aos encantos no Windows 8: o que são e como usá-los ):
Move your mouse cursor to the top or bottom right corner of the screen, then move the cursor up or down towards the transparent charm icons that appear in the middle of your screen.