These make fantastic appetizers before a larger seafood feast, or, if you use big Dungeness crab shells as I do here, a light supper all by itself. You can refrigerate the mixture for a few days beforehand, and you can freeze the stuffed crabs, well wrapped, for a few months.
Cook the onions in the olive oil in a small pan over medium heat until they turn translucent, a few minutes. Add the garlic and minced chile and cook another minute or two. Turn off the heat and let this cool for 10 minutes or so.
Meanwhile, in a large bowl, add all the remaining ingredients, except for the melted butter and the citrus. Mix well. Preheat the oven to 400F.
When the onion mixture has cooled, mix it into the crab mixture. Stuff the mixture into cleaned crab shells or whatever else makes you happy. Drizzle the melted butter over the stuffed shells evenly.
Bake for 20 minutes, and serve with wedges of lemon or lime.