Full list here

http://www.gog.com/en/forum/the_witcher_2/q_assassin_conjurer_strong_back_and_other_abilities_may_contain_spoilerzz

But it doesn't answer OP's question.

There we go! And, I'd assume the obvious answer is you just have to parry enough times.

If 'we'd go by the obvious answer, you wouldn't get "pyromaniac" by repeatedly into campfires, that's just silly.

It kind of sounds logical, maybe . i took swordsman path on my both playthroughs (didnt check for this ability on the other one) . Did anyone else playing on swordsman path get this?
I'm assuming they too wouldve parried enough times

Or it might have something to do with manual counterattacking, dunno really, just a thought.
Hope someone works out the correct method.

Confirmed, just got that in the prologue :)

[that's for pyromaniac btw]

EDIT: Nevermind, I just got this myself in the prologue. It took about 10-15 times walking into a campfire, without waiting to burn, and using Quen to extinguish myself.

There's a handy circle of health regen near one of the campfires.