Unfortunately (?) there were no damages.

To fill in the story, I was riding down the street, the bus pulls out to pass me (across a solid yellow line at that), the light changes and traffic was oncoming. The driver wants to merge back in but there's no place for me to go other than into a line of parked cars. I give the driver the "stay back" hand and he taps me with the bus. I almost lost control but didn't.

So I suppose I can sue for assault, but it doesn't seem like I have much of a case without any damages.