Rinse sticky rice until the water runs clear, then soak for at least 4 hours or overnight.

Steam soaked rice for 20–25 minutes until tender.

In a small saucepan, heat coconut milk, sugar, and salt over medium heat until the sugar dissolves (do not boil).

Reserve 1/4 cup of the coconut sauce for serving, then pour the rest over the hot sticky rice. Stir gently, cover, and let sit for 10–15 minutes to absorb the flavor.

Lay a sheet of banana leaf or plastic wrap on a flat surface. Spread a thin layer of sticky rice into a rectangle.

Arrange mango slices along one edge of the rice.

Carefully roll up the rice using the banana leaf or wrap to help shape it tightly.

Slice into portions and place on a serving plate.

Drizzle with the reserved coconut sauce and sprinkle with toasted sesame seeds if desired.