The awesome Jazzmutant Lemur. It's a touch activiated controller that is compatable with many DAWs such as ableton, logic etc. You can customise the entire set up of the controller as well which means triggers, faders and general fx control can be placed wherever you desire on screen and can be designated to whichever control you want. You can also get jazzmutant lemur software for an ipad as well which is the cheaper option as the Lemur itself is rather pricey.
Hahn also uses a MIDIfighter on-stage to trigger samples, replacing the nanoPADs he used throughout 2010 and 2011.