Soak the rice in 300ml of water for 30 minutes to 4 hours.
Drain the rice and wash it thoroughly under cold water.
Line a steamer with pierced greaseproof paper or muslin.
Steam the rice over 425ml of boiling water for 20 minutes.
Warm coconut milk, salt, sugar, and lime leaves in a pan without boiling.
Infuse the coconut mixture over medium heat for 7 minutes while stirring.
Arrange sliced papaya on plates and dress with lime juice and zest.
Combine the cooked rice with 300ml of the infused coconut milk.
Cool the rice for 15 minutes and drizzle with the remaining 100ml of milk.
Serve the rice with the papaya salad and optional mint garnish.