Hi,
I'm a dog owner and a place where we could go, off leash, in Lynn would be great. I don't think the beach idea wouldn't go over too well. We already can use it Oct. 1-May 1. Same goes for the Lynn woods. Many people use it for different things, running, dog walking, biking, scouting activities.
One area that would be great is the field that the college owns on the corner of Washington. It's never used, except when they are landing a helicopter for a movie

(The Surrogates). But I know some dog owners have been kicked out of there before. Some owners don't clean up after their dogs.
We actually go up to Salem and use the dog park by the Train station. It's only $25 for the year. The area is huge and fenced in. Next year they are bringing in water and making a small dog area. It is run by the parks and rec department, they make sure every dog is licensed and has all their shots and you get a tag. I think they got it started with a grant or donation and had a piece of land that was aquired after the MBTA station was built. Plus most owners are responsible and make sure all the dogs have a tag or will get one and the dog officer does frequent checks.
If Lynn were to do it, they should model it after the one in Salem. It has been a success. I haven't lived in the area for that long so I'm not to familier with areas that could be used, but it's a cause that I would support.