In a bowl, combine lukewarm water, sugar, yeast, and set aside for about 5 minutes until the mixture is frothy.
In a large bowl, combine all-purpose flour and salt. Add coconut milk, melted coconut oil, and the yeast mixture. Mix the ingredients together until it comes together, and take it out onto a clean surface.
Knead the dough for about 5 minutes until it forms a smooth ball. Put the dough in a large bowl greased with coconut oil, cover, and let it rise about an hour until it's doubled in size.
Gently deflate the dough in the bowl and take it out onto your work surface. Separate the dough into 12 equal balls. Place the balls in a 9x13 inch pan greased with coconut oil, cover, and let it rise again for about 45 minutes.
While the buns are rising, make the sweet coconut sauce. In a small bowl, combine coconut milk and sugar. Set aside.
Preheat the oven to 350°F/180°C.
Pour about ⅔ of the sweet coconut sauce over the buns and bake for about 30 minutes.
Once the buns come out of the oven, pour the rest of the coconut milk mixture over the top.