The dinghy dock is still under construction, but a new place has opened in Playland Park, Rye, N.Y., called Pier Restaurant & Tiki Bar
It's on the site of the old Captain Hook fast-food joint, but much enlarged. Run by proprietors of Seaside Johnny's in neighboring Oakland Beach, Rye.
The dinghy dock will be on the north side of the old steamboat pier, opposite the side that faces the swimming beach. Looks like Playland Park management has removed the six mooring balls it had put in (and never maintained) many years ago.
Edit: The dinghy dock is NOT under construction. Work underway is routine maintenance to the steamboat dock. A more-recent visit from the shore side shows no progress on the proposed dighy dock, and a fence still blocks access from the landing beach on the north side of the steamboat pier.
Write-up from local paper is here