Step 1 Prepare the spinach by cutting off the stems and separating the leaves. Carefully wash the spinach in several changes of water.
Step 2 Place the wet, clean spinach in a large frying pan over medium-high heat and cook until it is wilted and bright green, about 4 minutes. Note that the spinach may need to be added in batches, a little more added as what's in the pan cooks down. When all of the spinach is wilted, remove from the heat and quickly add the ice cubes to stop the cooking process.
Step 3Drain the spinach and squeeze it vigorously two or three times until as much water is removed as possible. Shape the spinach into a ball and slice four or five times so that it's in bite-size pieces.
Step 4In a medium bowl, combine the soy sauce, sesame oil, sesame seeds, garlic, rice vinegar, green onion and sugar. Add the spinach and thoroughly massage with hands. Chill in the refrigerator until serving. Serve in a small bowl, garnished with a sprinkle of sesame seeds.