Thank you for the information. Based on what you have told me, I do not think these are mites, I think you are picking up some of the little critters that are sometimes found in with crickets and are harmless, but a pest. Either way, lets be safe and do the routine cleaning and soaking that will get rid of the them in his enclosure and off him, just in case they are.
Prepare a box, sterlite or rubbermaid tub for him as a temporary house after you have cleaned him. You can soak him in plain water, up to his shoulder, leaving him in for 15 minutes or you can also add some iodine in with it till it is a weak tea color (this is not going to harm him but will make anything on him jump off. Check his head and you see anything heading there, pick them off and put in the water. You can use a clean toothbrush on his neck, around his legs and in any other skin folds. When finished, rinse him off well dry and place him in the temporary housing.
To clean the enclosure, remove the sand, you are going to need to replace it as it probably has eggs in it. Soak the stone or any other furnishings in the same tub of iodine water or hot soapy water if you did not use the iodine mix, rinse really well and let dry. Wipe down the enclosure with the iodine mix or nolvasan or any germicide cleaner. You can also use as hot as you can stand it water and soap, letting it soak on the bottom of the tank for 15 minutes. Reset up his enclosure for him with the cleaned furnishings and new substrate.
Just for general information, dragons are sun lovers and thrive best with an over head heat source, even a plain household light in a dome is better for them than under tummy heat. They can no accurately sense heat on their tummies and also will get bacteria or yeast over blooms in their digestive tracts from the constant heats. They need a cooling period over night to rest well. Thy should be in basking temps of 95-105F and cool areas of around 80-85. I recommend a digital probe gage that you can buy online or from Wal-Marts for $7-$10.
The over head UVB (make sure it is UVB) tubes are good if you are using a ZooMed ReptiSun or a ExoTerra ReptiGlo, all others do not produce enough UVB for them. You can also buy the UVB and heat in one lamps, that screw in, like the MegaRay, Active UV Heat or PowerSun that delivers both over head and I will add a photo of that below
If sand is working well for you and not causing any bacterial problems, smell or him ingesting any of it, that is fine for him, but there are many safe, easy to clean substrates to use, such as tile, linoleum, butcher paper, paper towels, reptile carpet, non adhesive shelf liner or combinations or them, that can be spot cleaned daily or washed every few week as needed. Here is a few photos to give you some ideas.
The first is a baby enclosure with over head UVB and heat in one light and an additional household light in another dome, with shelf liner, small carpet areas (until they are trained)and also a paper towel area for poo.
And here is an adult on the same
This really keeps down the bacteria and bugs. It is very easy to clean and also control parasites in them.
Please let me know if you need any more help with this