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

Drain and place the rice in a heatproof bowl in a steamer over boiling water, cook for 20-25 minutes until tender.

In a saucepan over medium heat, combine coconut milk, sugar, and salt; stir until sugar dissolves and heat until warm.

Add cooked rice to a mixing bowl, pour in one cup of coconut sauce, and fold to combine. Let sit for 10 minutes.

Serve sticky rice on a plate, arrange mango slices alongside, drizzle with remaining coconut sauce, and sprinkle with sesame seeds.