If your rice cakes are chilled, boil them in water for 2 minutes until they are soft. Put the rice cakes in a bowl and add a pinch of salt and sesame oil; toss and set aside.
Heat the oil in a skillet over med-high heat. Saute the onion until golden brown, about 4-5 minutes. Add the rice cakes and cook for another minute.
Add the beaten eggs to the skillet and stir around. Cover with the lid and let them cook for 1 minute. Uncover and continue to stir until the eggs are fully cooked. Season with salt the pepper according to your taste. Sprinkle with green onion (or chives) and serve hot. Drizzle with a few dashes of hot sauce if you like.