Cut off and discard the thick stem of the spinach.
Dip the spinach in a large vessel of water and let it sit for a minute to loosen any dirt or soil. Drain and wash the spinach and repeat.
Bring a large pot of water to a boil.
Add the spinach leaves, stir to submerge in the boiling water, and blanch them for 30 seconds to 1 minute.
Take out the spinach leaves with a tong and immediately soak in cold water to stop the cooking process.
Squeeze out excess water - but not all the liquid from the leaves and stems.
Then roughly cut the spinach into 1-2" length and put them in a bowl.
Heat oil in a preheated pan, add garlic, and chili. Stir fry for 10 to 20 seconds or until just fragrant.
Add spring onion and stir fry for about 20 seconds.
Add spinach, soy sauce, and salt to taste. Stir fry the spinach to coat and mix with the oil and seasoning.
Remove from flame and serve hot, adding toasted sesame seeds.