Make the crepes: Combine the milk, egg, flour, cocoa powder, confectioners' sugar, 1 tablespoon melted butter, the vanilla and salt in a blender; pulse until smooth.
Lightly brush a 10-inch nonstick skillet with some of the remaining melted butter; set over medium heat. Pour in 1/2 cup batter and swirl to coat the bottom of the pan; cook until almost set, about 4 minutes. Flip with a rubber spatula and cook until set, about 2 more minutes. Transfer to a baking sheet and let cool. Brush the skillet with more butter and repeat with the remaining batter to make 3 crepes.
Make the filling: Preheat the oven to 375 degrees F. Spread the coconut on a baking sheet and bake until toasted, about 10 minutes; let cool.
Beat the butter, confectioners' sugar and vanilla in a bowl with a mixer on medium speed until smooth. Spread on the crepes, leaving a 1/2-inch border. Sprinkle with the coconut.
Starting about 1 1/2 inches from the bottom of each crepe, arrange the kiwi, mango and raspberries in horizontal strips. Fold the crepes over the fruit to cover, then tightly roll up. Chill until firm, about 1 hour.
Cut the crepe rolls into pieces. Thin the dulce de leche with 1 tablespoon water; serve on the side.