Rinse the glutinous rice under cold water until the water runs clear.
Soak the rice in water for at least 4 hours or overnight.
Drain the rice and steam it in a bamboo steamer or a heatproof bowl set over boiling water for 25-30 minutes, or until tender.
While the rice is steaming, combine the coconut milk, sugar, and salt in a saucepan.
Cook over medium heat, stirring occasionally, until the sugar is fully dissolved. Do not let it boil.
Remove from heat and set aside.
Once the sticky rice is cooked, transfer it to a large mixing bowl.
Pour 1 cup of the warm coconut sauce over the rice and stir to combine.
Cover the bowl and let the rice absorb the coconut sauce for about 20-30 minutes.
Arrange the sticky rice on a serving plate.
Place the sliced mangoes alongside the rice.
Drizzle the remaining coconut sauce over the rice.
Garnish with toasted sesame seeds if desired.
Enjoy your meal!