In a mixing bowl, whisk together the glutinous rice flour, cornstarch, and white sugar until well combined. Gradually pour in the coconut milk while continuously stirring to create a smooth batter. Once blended, strain the mixture through a fine sieve to remove any lumps.

Set up a steamer by bringing water to a boil. Pour the batter into a heatproof dish lined with parchment paper, then place the dish in the steamer basket. Cover and steam for 25 minutes until it's firm and cooked through.

After steaming, remove the dish and let the dough cool for about 10 minutes. Add the coconut oil and mix thoroughly. Wrap in plastic wrap to maintain moisture.

Divide the dough into 10 equal pieces. Roll each piece into a ball, flatten it, and place a small ball of red bean paste in the center. Fold edges to seal and roll in shredded coconut.

Place each piece in a cupcake liner for presentation and allow to come to room temperature before serving.