Soak rice in water for 4-10 hours. Drain into a colander. Add 1 cup water to the insert of the Instant Pot/pressure cooker. Using a steamer basket that will fit inside the bowl of the Instant Pot, add the soaked and drained rice. Close and lock the lid.
Set the pressure cooker on the manual setting on high for 12 minutes.
While the rice is cooking, combine the coconut milk, dates, vanilla and salt into a blender and puree until smooth. Set aside two-thirds of it.
In a small saucepot, heat the remaining one-third of the coconut liquid. Bring to a boil and whisk in the arrowroot slurry. The coconut milk mixture will thicken. Turn off the heat.
Allow the pressure in the Instant pot to release naturally for 12 minutes and then manually release. Unlock the lid. Take out the steamer basket. Stir in ⅔ of the coconut milk-date liquid. You can leave the rice on the warm function.
Mound the sticky rice onto a plate. Add the mango, spoon the sauce over it and sprinkle with sesame seeds, lime zest and lime juice.