Jimmy Fallon -- Plastered in the Hamptons (PHOTO)

Jimmy Fallon's healing his aching left hand in style ... hitching a ride to the Hamptons to close out the holiday weekend.

Jimmy's injured fingers and hand were fully wrapped in a cast Sunday in Manhattan as he hopped a helicopter bound for the Hamptons -- 10 days after he nearly lost a digit falling at home.

The 'Tonight Show' is in repeats now ... so we're guessing Fallon's using his time off for some quality R&R out on the Island.

Little advice, Jimmy? Keep that thing out of the sand.