This one is at Coulon Beach in Renton, and also in Enatai Beach Park in Bellevue. See http://www.canoe-kayak.com/site/locations.php?action=details&id=2
for more information. They rent by the hour, teach classes for children and adults and sponser a variety of trips -- sea kayaking, San Juan Islands, etc. The staff is very friendly even if you're not buying or renting, and the trail along the Cedar River from the parking area is very popular.