I was there in mid-june this year and stayed on the NW side of Aitutaki.
Many parts of the lagoon have coral reefs just below the surface, so aren't really suitable.
I launched one day from near "samade's on the beach"
around about here:
www.google.com.au:443/maps?f=q&source=s_q&hl=en&geocode&q=Aitutaki,+Cook+Islands&sll=-21.289374,-161.894531&sspn=27.540543,50.625&ie=UTF8&hq&hnear=Aitutaki,+Cook+Islands&ll=-18.847152,-159.761124&spn=0.000861,0.001545&t=h&z=19then I headed south and had plenty of room then came back to samades for a beer and lunch :)
not the greatest launch spot so assisted it probably the way to go.
Its pretty much always a SE wind.
But i can totally recommend going out to honeymoon island with the guys from south pacific kiteboarding. I emailed them, got a lift in their boat to the island and was out all day for a very modest fee. They dropped me off to my hotel too.