I grate it.
carrots in meatloaf and cole slaw. onions in a lot of things. potatoes and cheeses of course. cinnamon sticks, nutmeg nuts. frozen butter in pastry or crumbles. sometimes a crumbly corned beef for hash. chocolate.
Citrus fruit zest
Assuming that others have correctly guessed the question- add tomatoes; a grater can fairly efficiently (depending on ripeness) remove the peel (you grate the flesh off the peel, not vice versa). Someone also mentioned a grater on the "bread crumbs" thread on this page.
medium-to-hard cheese; citrus zest; potatoes (in the food processor); fresh ginger; fresh garlic (sometimes).