What is a beach that projects like finger out into the water?

A beach that projects like a finger into the water is often referred to as a "spit." A spit is a narrow landform made of sand or shingle that extends from the mainland into a body of water, formed by the processes of longshore drift and sediment deposition. These features can create sheltered areas behind them, often leading to unique ecosystems and habitats. Examples include the Cape Cod Spit in Massachusetts and the Spit at the entrance of the Thames River in the UK.