I have heard it recommended to pre-rinse rice hulls before putting them in the mash. Mainly because they tend to be so dusty. Is that a good practice?
I think it's personal preference. They are usually quite dusty, so some brewers rinse them in warm water, which they claim also helps by preventing them from needing to adjust their strike temperature for the addition of hulls.
If you're brewing a lighter beer, like a wheat, it's a safer practice to rinse so that you can be sure that your beer color comes out right. However, if you're brewing a darker beer, you won't be able to tell a difference in the end product.
From what I've seen, I think most brewers don't rinse their rice hulls.