I'm rather fond of chocolate coated citrus rinds, so when I peel my citrus fruit, I make sure I peel it in sections. Then I freeze it. That way, I've always got enough rind to coat with chocolate when I get the urge (I just cut it into thin strips); and I've always got plenty of rind for grating (it's easy when it's frozen). If I want a lot of grated rind, I zap it through the food processor. When coating with chocolate, the white pith stays on (unless it's really thick), but for grated rind, you need to remove the pith. It's easy if you use a teaspoon.
If you wanted just the grated rind, pack it into a plastic bag and squash it flat like a pancake. Make layers if you like, with plastic wrap in between. That way, you can break off small pieces as desired - no need for a hammer and chisel!
