Both dulse and nori are made from red algae, although they vary slightly, they are close enough to be considered substitutes. Flavors will vary as with any natural product. I would say, Billster, that pounding or flaking of nori would work fine. I can't believe you would need a giant Thai mortar and pestle, I suspect you just want to use it, which is what I would do too.
me: I don't drink anymore
Yelonutz: me either, but, then again, I don't drink any less