Preheat the oven to 325°. Line a 9-by-13-inch baking pan with foil. In the top of a double boiler or in a microwave-safe bowl, melt the chocolate with the butter. Stir well and let cool.
Spread the coconut on a rimmed baking sheet in a thin layer and toast in the oven for about 7 minutes, until light brown and fragrant. Season the coconut with 1/2 teaspoon of the salt.
Meanwhile, in a large bowl, beat the eggs with the sugar. Using a rubber spatula, gently fold in the cooled chocolate mixture. Sift the flour, cocoa powder and the remaining 1/2 teaspoon of salt over the mixture and stir until incorporated. Pour the batter into the prepared pan and bake for about 20 minutes, or until a tester inserted in the center comes out with fudgy crumbs attached. Transfer the pan to a rack and let the brownies cool completely.
In a microwave-safe bowl, heat the dulce de leche in the microwave until bubbling. Drizzle the hot dulce de leche over the brownies and sprinkle evenly with the toasted coconut. Let cool.
Lift the foil to remove the brownies from the pan. Place on a cutting board and cut into 24 brownies. Arrange on a platter and serve.