First, a little about how the control surface works. The touch sensitive areas on the DaScratch controller all respond to multiple simultaneous touches. And control areas can be used at the same time, so it's possible to adjust (for instance) 3 sliders at the same time.
Knowing that, a finger jump is when you touch 2 points at the same time on the same control area. A good example is the GAIN slider. If you take one finger and place it on the bottom of the slider area, it will register a low value. If you hold that lower finger there and then put another finger higher up on the slider, the value of the slider will jump to the higher value. So if you wanted to do a transform like effect with the gain slider, you would put one finger at the top of the slider, then tap a pattern using another finger on the bottom. When your finger hits the lower value, it will kill the channel gain - but only for as long as your other finger is on the slider. Other cool effects can be achieved using other modes (try it in circle mode ot vinyl mode in a preset).