Prepare the Water: Boil water in a pot.
Blanch the Spinach: Blanch the spinach in boiling water without a lid for 30 seconds to 1 minute, depending on the thickness of the spinach.
Cool and Clean: Immediately cool the blanched spinach under cold running water to stop the cooking process and remove any remaining dirt or mud.
Squeeze Out Water: Squeeze out the excess water from the spinach.
Season the Spinach: In a bowl, combine the spinach with minced garlic, chopped green onion, soy sauce, and sesame oil. Mix well.
Serve: Optionally garnish with sesame seeds and silgochu for color. Serve as a side dish with rice or noodles.