Since this post, the OpenSesame runtime has been ported to Android. This provides an even easier way to run experiments on a tablet device. For more information, see http://osdoc.cogsci.nl/getting-started/android/.
As you can see in the video below, it is possible to run OpenSesame on a tablet! This way you can take your experiments anywhere.
I will post more detailed instructions on the OpenSesame documentation page soon, but for now some basic info should get you started: The operating system that you see in the video is Ubuntu Linux. The tablet is a Nexus 7. Installing Ubuntu onto a Nexus 7 tablet is a straightforward process, and so is restoring the device to it's factory settings. Once you have Ubuntu running on your tablet, you can install OpenSesame directly from the Cogsci.nl PPA.