My guess (just a wild one for not being a thinker of touch interface design), would be to solve the solution by first detecting what kind of flash app it is and how much area it takes up, then anytime the finger scrolls over that particular area, there would be a cursor (the user could turn this off, but this is what would happen by default). As the cursor is led by your one finger which never lets up, meanwhile 1,2, 3 or 4 taps with another finger along with other more complex combinations eventually could perform various flash actions. Contrary to Dilger's primary thesis, I believe it's pretty straight forward that Apple is not as limited in thinking to make it happen if they want to, and that even the general audience is ready to take another small step in the gestures department.