Drizzle a small amount of olive oil into a preheated pan over medium heat, then add green onion, onion, and oyster sauce, mixing them together.
Add 1 tomato diced into bite-sized pieces and stir-fry.
Beat 3 eggs with a pinch of salt, pour them into the pan, and stir-fry quickly over high heat.
When done, transfer to a plate and sprinkle a small amount of black pepper on top.