I was in Hikkaduwa last November doing some surfing ... spoke with the only guy I know who Kites over there and he said Arugambay might be ok if the wind is cross-shore ... Arugam surf season is June/July/Aug - you wouldn't want to be there in the off-season, as it's a mess ...
Don't forget to side-step the Tigers by taking the southern route to the 'bay' !
Hikkaduwa is supposedly good Feb/Mar ...
If you want some more info you could possibly try: www.boutiquesrilanka.com/interests_water_land_sports.php