Step 1

Bring a medium pot of salted water to a boil. Stir in the rice and boil until just done, about 10 minutes. Drain the rice and set aside to cool.

Step 2

Meanwhile, in a large nonstick frying pan or wok, heat 1 tablespoon of the cooking oil over moderately high heat. Add half the mushrooms and cook, stirring frequently, until the mushrooms are tender and golden, about 5 minutes. Transfer to a plate. Repeat with the remaining mushrooms and another tablespoon of the cooking oil. Add these mushrooms to the plate.

Step 3

In the same frying pan, heat the remaining tablespoon of cooking oil over moderate heat. Add the red-pepper flakes, ginger, and scallions and cook, stirring, until fragrant, about 30 seconds. Increase the heat to moderately high and add the rice, salt, and soy sauce. Cook, stirring, for 2 minutes and then add the peas and mushrooms. Cook, stirring, until everything's warm, another 1 to 2 minutes. Remove the pan from the heat and stir in the sesame oil.