Hey guys, it is indeed some 'wizardry' which requires some programming. Basically I do it by sending OSC values to Arena to have things fade out thus creating that overlapping animation.
As Joris mentioned you should start making an input mapping and from there you can do anything. The quickest approach is (after making an input map) using Joris' plugin Chaser. Then you can throw in a solid and chase with a press of a button.
My method of doing it is using a plugin we released recently called Mapper. But for this I use Processing to intercept Midi messages and translate it to OSC. It is more difficult to explain though