Fill a stockpot with water and bring to a boil over high heat. Add green beans and pinch salt; boil until tender, 5 to 10 minutes. Drain beans in a colander and rinse with cold water. Blot dry using paper towels.
Heat olive oil in a skillet over medium heat. Cook and stir onion and shallot in hot oil until tender and translucent, 5 to 7 minutes. Add green beans and season with garlic salt, soy sauce, salt, and pepper. Cook and stir for 5 to 7 minutes more. Serve immediately.