The Flash issue is an Adobe bug that, probably, they will refuse to fix. You're right to say that they totally borked the colorspace. On the nvidia forums (nvnews.net) there is a thread about it with a really awful hack that nvidia devs came up with to work around Adobe's obstinate stupidity. It's probably easier to just disable hardware acceleration like you say. That's the route I chose.
As for the tearing, I can't say. It may be compiz related. Is sync to vblank turned on? You're not using TwinView, are you? Does it still tear if you login to Unity2D instead?