Actually the launches will put you pretty close to the water, but parking can still be a bear. I bet that you can find a park in the Bellevue area with waterfront access, I usually fish off of the west side of Mercer Island, but that can be a haul in a canoe.

My canoe is an old Herters 15' aluminum. Had it since I was 10 and I still use it regularly to fish and hunt from. It can be safe as long as you realize the limitations.
I had a few frightening experiences with mine duck hunting on the Nisqually flats area. Once my canoe floated across a slough after the wind blew it off of the mud. I had to swim across the slough to get the boat. Cold day! Same place, different day, I had hunted all day long in good duck weather, windy, but when it was time to go in, there were white caps and rollers present in the channel that I had to cross. Could not have gotten a needle up there with a jackhammer, if ya know what I mean!
These were exploits from my younger, less intelligent days. Please learn from my mistakes, and wear your lifejacket.

Be safe, and keep the open side up!