Heat 1 tablespoon of vegetable oil on a large frying pan over medium-high heat. Add the shrimp and cook for about 3 to 4 minutes, until they start to turn orange. Flip the shrimp over and cook a few minutes more. Transfer the shrimp to a plate.
Crack 2 eggs into a small bowl and beat them together. Beat the last egg in a separate bowl.
Heat a large sauté pan or a wok with 1/2 tablespoon of the vegetable oil over medium-high heat. Once the pan is hot, add the 2 beaten eggs and scramble them for about 30 seconds, until they're fluffy and no longer runny. Transfer the eggs to a dish and turn off the heat. Wipe off the pan or wok with a damp kitchen towel.
Drizzle the remaining 1 1/2 tablespoons of oil in the pan or wok over medium-high heat. Add the onions and cook them for about 2 minutes, stirring constantly. Add the ginger, and cook for another minute. Next, add the mixed vegetables, scallions, and salt and cook for another 1 to 2 minutes. I like to save some of the scallions (the dark green part) for garnish.
Add the cooked rice into the pan or wok and cook for a few minutes, until the rice is heated through. If you have large clumps of rice, break them apart with the back of your spatula. Pour the single beaten egg over the rice and stir to coat the rice with the egg. Cook for another minute.
Add the soy sauce and sesame oil and stir to distribute the seasoning. Add the cooked shrimp and egg to the pan and stir again. Turn off the heat. Serve the fried rice immediately.