To make the riceSoak the rice for 30 minutes in cold water. This step is important to ensure that the rice cooks evenly and absorbs moisture evenly, which gives it a better texture and flavor. You want them to be sticky but not a gooey clump. Soaking them and then rinsing them do this!
Rinse the rice by placing the rice in a metal strainer and dunking it into and out of a bowl full of clean water. Change the water out and continue until the water stays clear when you rinse it. This will help the individual grains of rice retain their shape and not turn into a pile of mush when you cook it.
Place the rice and 2 cups of water into a large saucepan. Cover with a lid, and turn to medium-high heat. Bring to a boil.
Once the water starts to boil, lower the heat to almost low, and cook for 15-20 minutes, or until the water is mostly gone.
In another pot, combine 1 cup of coconut milk and ¼ cup of sugar. Simmer until the sugar dissolves, about 10 minutes.
Slowly add the coconut mixture to the cooked rice and allow it to sit for 30 minutes.

Make the sauceIn a small saucepan on low heat, add the remaining sugar and coconut milk and allow it to cook until thickened, about 10-15 minutes.

To serveServe the sticky rice with sliced or cubed mango, drizzled with the coconut sace, and sprinkled with sesame seeds.