To prepare pastry cream, cook milk, coconut milk, coconut and salt in a saucepan over medium heat to bring the mixture just to a boil. Stir occasionally.
While the milk is cooking, in a bowl whisk together egg yolks and sugar until the mixture becomes pale. Add cornstarch and flour, mix until smooth.
Slowly add 1/3 of milk mixture to egg mixture, whisking continuously. Pour the milk-egg mixture back to the saucepan. Cook over low heat and whisk continuously until the custard is thickened, about 3 to 4 minutes. Remove from heat.
Pour the custard through the sieve and into a bowl.
Let cool for 15 minutes. Put a plastic wrap right on top of the cream to prevent skin forming. Refrigerate until cold and set, at least 3 hours or up to 2 days.
To prepare cream puff shells, preheat oven to 400F. Grease two 24-cup or one 48-cup mini muffin tin.
Bring water, butter and salt to a boil in a medium saucepan. Add flour all at once and stir vigorously with a wooden spoon until the mixture begins to pull away from the sides of the pan and comes together in a ball, about 2 minutes.
Remove pan from heat. Let cool for 10 minutes.
Transfer dough to a food processor. Beat in the eggs one at a time, fully incorporating after each egg addition. The mixture will become smooth and glossy.
Scoop a tablespoon into each muffin tin. Use a wet finger to smooth out any rough spots on top of the dough.
Bake for 20 minutes until the tops are golden brown.
Remove the pan from oven. Immediately use a toothpick to pierce the side of each cream puff, pull it out of the tin and onto a wire rack to let cool completely.
To prepare ganache, place the chocolate, heavy cream and corn syrup in a medium heatproof bowl over a pot of simmering water. Stir the mixture using a wooden spoon until melted and smooth. Let cool slightly.
To assemble, cut a slit in a cream puff shell, fill with one tablespoon pastry cream. Grab it with its bottom, dip it in ganache to coat the top, let excess drip off. Place on a serving plan and sprinkle with coconut. Repeat with the rest.