It depends on the beach.
We boondock on the beach @ Port Aransas every year, for a few days, and the sand is hard. I just level right on the sand. One time i did have a jack punch into the sand. I retracted and moved 2 feet and was good to go. The soft spot must have been someone digging for treasure at an earlier date.
If your tires don't sink in you can level on the sand if they do sink then use weight spreaders (2'X2' plywood).
2003 Class C, 29' Gulfstream
Previous rigs..2 Pickup campers,2 TT's, 3 DP MH's