Bring about 3 inches of water to boil in a medium-sized pot.
Whisk together eggs and water in a small bowl that's about 6 inches tall (this bowl will go into the boiling water, so make it's not plastic or anything). Make sure eggs are well-beaten and frothy.
Add salt and sesame oil to the eggs, and mix well again.
Place the bowl carefully into the pot of boiling water. Reduce heat to medium-high. Water should be boiling gently. The height of the water should be about halfway up the bowl. Make sure the water does not boil into the bowl (if it does, remove some of the water).
Cover and let steam for about 10 minutes, then add the sesame seeds and green onions to the eggs. Do not stir (they should just be resting on surface of egg).
Cover again. Cook for about 15-20 minutes or until the eggs start to pull away from the side of the bowl and it has completely set.