Rinse the sticky rice under cold water until the water runs clear, then soak in fresh water for at least 1 hour or overnight.

Drain the rice and place it in a heatproof bowl fitted over a steamer. Bring water to a boil and steam the rice for 20-25 minutes.

In a saucepan, combine coconut milk, sugar, and a pinch of salt. Heat over medium flame until sugar dissolves completely.

Once the sticky rice is cooked, transfer it to a large bowl. Pour part of the coconut sauce over the rice and stir.

To serve, portion the sticky rice onto plates, arrange mango slices beside it, and drizzle with more coconut sauce. Sprinkle with sesame seeds.