Heat the coconut milk, sugar and salt in a saucepan over low heat until sugar just dissolves. Pour about half of the mixture over the cooked sticky rice and mix well. Add coconut cream to the remaining mixture and heat to a boil, then cook 5 to 10 minutes until thickened. Allow to cool. Place the rice in a serving bowl, top with sliced mango and drizzle with the coconut cream mixture. Serve at room temperature.