The largest open space immediately adjacent to the Second Street sidewalk is on the block between Folsom and Harrison. It's recently been given a total rehabilitation from it's original 1980s design. Bordered by restaurants, it's a great place to eat your lunch in the sun on the grass and people watch. Though privately owned it feels public with no separation from the street.
Sunny grassy lawn at Marathon Plaza.
Marathon Plaza is currently the best open space along Second Street.