Line a baking sheet with parchment paper and set aside.
Melt the chocolate in a double boiler. When the chocolate is melted, stir in the cayenne, ¾ of the orange zest and ¾ of the toasted almonds. Spread the chocolate mixture onto the prepared sheet, being sure to smooth it into as thin a layer as possible. Sprinkle with the remaining zest, almonds and a generous pinch of coarse sea salt. Place the baking sheet in the freezer until the chocolate is firm, about 30 minutes. Break into pieces and store in an airtight container.