How about [shift]+[delete]
Also, for cartoon styles you may want to switch the paint mode to (=) rather than (>). That's the little button next to the paint action icon. Or simply hit [m] twice to get to this mode. [m] rotates through the paint modes, you know. If you're on (=) you will have a fixed material build-up that clamps at 1.0. This will avoid the heavy streaks or excess build-up.
Cute style, by the way!
For pressure control, you can always bring up your wacom properties, too, and adjust the curve there, while I work out finer controls in Verve. There are a few challenges in the fundamental behavior of Verve, making this stuff somewhat trickier than in "ordinary" painters.