Splashtop is an app to connect from an iPad (or iPhone) to a Mac/PC that are in the same WLAN; real internet access is available for a monthly or annual fee. Splashtop is robust and fast. Of course it does not replace a full fledged desktop environment, but it gets the job done if you don’t have physical access to your computer. Small control elements, like in Aperture above, can be zoomed with spread and pinch gestures.