Know any asian drama about a girl who know's how to fight?

definitely watch:
siren (jdrama) : both female leads are strong and especially the female villain really does know how to fight, she's probably stronger than yankumi from gokusen lol, also there's romance and a lot of unexpected plot twists until the very end, refreshing drama

Empress Ki

Decoded

Mrs. Cop

Make a Woman Cry

City Hunter- The female lead was a bodyguard, and is very capable of holding her own in a fight. 

Bride Of The Century. Lead female is a no nonsense girl, there isn't a whole lot of fighting bt whenever it happens she 
kicks ass. Really more of a romance, slow build up and lead male is a musician in real life so it's up your alley :)
Don't let ratings or reviews decide for you, check it out and judge for yourself.

I almost forgot Mirai Nikki, but that one doesn't have too many fight scenes..
Also, I haven't seen it yet, but Kuroi 10-nin no Onna has a couple of fight scenes, from what I've heard. The drama Lucky Seven might have some, too, but I'm not sure on that one, sorry....

Gu Family Book! She is dressed like a guy and knows how to fight (there's also a beautiful love story :) )
Rurouni Kenshin (she's a martial art teacher)
Hello Monster (She's a Cop)
You're All Surrounded (same)
Legend of the Blue sea (she's just like Bruce Lee xD)

Hope you haven't seen all of them already!  :)

http://mydramalist.com/10117-mook-liam-petch  - the female lead is a spy,so she is strong unlike her look. This is a very good Rom-Com + exciting + revenge plot.