1. Preheat oven to 350 degrees. Place nuts on a baking sheet. Bake until fragrant and toasted, about 12 minutes. Transfer to a clean kitchen towel; rub to loosen skins. Place sugar and water in a medium heavy skillet. Stir with a fork over medium-high heat until dissolved; let boil undisturbed for 3 minutes. Add nuts to pan; stir with wooden spoon until caramel seizes around nuts. Transfer to parchment-lined shallow baking sheet; let cool.

2. Once nuts are cool, place half of chopped chocolate in a deep medium-size stainless-steel bowl. Place bowl over a saucepan with 1 inch of simmering water; stir until chocolate is melted and hot. Add remaining chocolate to bowl, remove bowl from pan of water, let stand about 5 minutes, then stir until smooth.

3. Pour half the chocolate onto an inverted baking sheet; spread with a bench scraper until 1/8 inch thick or slightly thinner (chocolate should be opaque on surface). Let stand until just tacky. Hold scraper at a 45º angle; scrape chocolate off surface. Store curls at room temperature in an airtight container layered with parchment.

4. While chocolate sets, add candied nuts to remaining chocolate in bowl, and stir until coated. Spread nuts on a parchment lined baking sheet, and let stand until set.

5. Sift cocoa powder on top of dried nuts and toss to coat. Store in a resealable plastic bag for up to 1 week, until ready to use.