Heat vegetable oil in a wok or large skillet over medium-high heat. Add onions, green chile peppers, garlic, and ginger; cook and stir until golden, about 2 minutes. Stir in soy sauce, white pepper, and salt; cook for 1 minute.
Stir prawns and squid into the wok; cook and stir until prawns turn pink, 2 to 3 minutes. Add spinach and carrot; cook until spinach is wilted, 2 to 3 minutes. Add noodles; toss to fully incorporate.
