I've been on Alki Kayak's tours a couple times, and it's always great. You need absolutely no experience (trust me, I had none) and shoes that can stand to get wet - you step into the water up to the calf or so when launching.
He goes through a brief "dummies guide to paddling" and then we're off. It'll be a blast.
If we do the "Happy Hour" sunset paddle on Tuesdays, it is cheaper. RSVP if you're interested, and include the day that works best for you, and if you have a preference of their tour types.