When I say hidden Shortcuts I mean that they are not present on the Custom Shortcut´s list of the last build (02Aug2013).
I was playing with Pencil like it was ArtRage instead, and took note of the following shortcuts.
I use a tablet with a pen.
Keep pressing the Right button plus moving the tool cursor to some direction (no need to drag the cursor) will allow to Zoom the CANVAS In and Out:
Moving Up will ZoomOut and moving Down will ZoomIn (faster way)
Moving Right will ZoomOut and moving Left will ZoomIn (slower way)
Keep pressing the SpaceBar will active the HandTool
Keep pressing the ALT+Right button will allow to Rotate the canvas. Making a circular move with the pen while pressing these shortcuts will rotate the canvas left or right. It is a bit tricky and it would be easier if dragging the pen against the canvas and making a circular move to get the canvas rotating.
EDITED: I realized that the tool cursor has to be at the CENTER of the canvas for the rotation of the canvas works properly, if not will happen the same thing @mikshaw mentioned bellow “Also the Alt+right mouse needs work…seems to be zoom + rotate”