In the last 90 days, 1 listings have been listed, which means listings most likley are going fast. You'll want to be prepared to make an offer immediately. About 200% of the available space in the Manhasset are subleases, so you might be able to sign a shorter term by taking over a previous lease. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 2,500 sqft. Most buildings in this area were built in 1983.