Not a question of "kicking ass", per say....It's the IMAGE that chicks really dig in a man. It's older than time itself....You look at men, the pop culture icons, like James Dean, Marlon Brando (The Wild One), ect....Guys who present an image of reckless independence and defiance....There's something very appealing in that, for women.
Primarily, it's a question of CONFIDENCE....Confidence, wether in a man or woman, is the sexiest attribute that one can possess.
Half of the time when confronted they turn tail and run anyway. They are all TALK. That's such a damn good feeling...either kicking the crap out of them or watching them run.