Rinse sticky rice and then soak in plenty of water for 2-4 hours. Also rinse then soak mung beans in plenty of water for 2-4 hours.
Drain the mung beans well and toss with ⅛ teaspoon salt. Then steam until they are soft, about 20 minutes. Remove from the steamer basket and let them cool slightly to let excess moisture evaporate.
Once the mung beans have cooled down, transfer to a food chopper/food processor and grind finely.
While steaming the mung beans in Step 2, drain the rice very well. You can also use paper towels to absorb excess water. The goal is to dry the rice as much as possible to prevent too much stickiness later. After grinding the mung beans, toss the drained sticky rice with half of the mung bean powder, remaining salt and cooking oil.
Transfer the sticky rice to the steamer basket and steam until soft, about 25-30 minutes. Then let it cool slightly.
Toss the steamed sticky rice with the remaining mung bean powder. If you see big clumps, you can use your fingers to separate the grains while rubbing them with the mung bean powder.
You can enjoy the sticky rice right away on its own, or with Vietnamese sweet dessert soups (such as mung bean pudding), or with roast pork, roast chicken.