I know of a field where the owner does not use any pesticides or anything and they have lots of dandelions roaming. I walk over there and take some because I know they don't do anything to it (they also pick their dandelions for their pets). You could try to find a place where you're sure the dandelions are safe to eat for your beardie, perhaps. Nothing better than free food!
Unfortunately, my beardie doesn't like dandelion leaves, lol.