Prepare the Cucumbers: Wash the cucumbers thoroughly and slice them into thin rounds or half moons. Place them in a bowl and sprinkle with the salt. Let them sit for about 20 minutes to draw out excess water.
Rinse and Drain: After 20 minutes, rinse the cucumbers under cold water to remove the salt. Drain well and pat dry with a clean kitchen towel or paper towels.
Mix the Dressing: In a large mixing bowl, combine gochugaru, minced garlic, chopped green onions, soy sauce, rice vinegar, sesame oil, and sugar. Stir until well mixed.
Combine: Add the drained cucumbers to the bowl with the dressing. Toss well to ensure each piece is thoroughly coated with the spicy, tangy mixture.
Garnish and Serve: Sprinkle the toasted sesame seeds over the top. Serve immediately or chill in the refrigerator for about 30 minutes to enhance the flavors.