Hi smbl,
as you can see on the huge number of replies
helicopterpilots know the answer but arenīt quite sure why you ask.....
Well, as long as the slope isnīt exceeding the helicopter limits, you can land on the beach
Unfortenuatly helicopters donīt like sand - its abrasive to rotor- and tailrotorblades and (6 people helicopter=turbine) turbines - as long, as you donīt have a filter (only turbine, not rotorblades).
Brownout is also possible during landing and take off - so a fixed pad would certainly be appreciated by the maintainers and the pilot.
Greetings Flying Bull