There are a coule of techniques. I have been out in the middle east for a couple of years, so generally dusty sandy conditions.
Operating every day in the desert. Sand is quite a different wee beasty, from place to place, it can differ due to size, moisture, temp and wind acting on it.
However some of the above answers are spot on the approach phase and general zero zero landing's, small run on, or slightly faster to keep the sand being generated in the 3 0'clock position as the skids touch the ground.
The extent of the sand and dust being blown and recirculated, is dependent on how big your chopper is, and how much wind you have on the nose.
There are many different wind finding techniques in the desert, standard military patterns low level, or low level you can see your downwash affect the sand and see in which direction it blows, or if a previous aircraft has landed before you, you can see the difference in colour change in some sand area's which causes a distortion in there overall downwash and acts like a great bigger pointer.
The one I like the best even if it is a bit silly is the camel theory.
If the camels are sitting down they generally will have their backside's pointing into the wind, so to keep the sand from blowing into their eyes.
However you have to have a wind speed of 15 kts and above for this generally to be accurate.
So for the camel approach you need : 1) A camel, preferably not blind.
2) One local paid, to hold the camel
3) 15 kts of wind.
All the best
fluffy 5