Prepare the cucumbers

• Wash the cucumbers and slice them thinly (use a mandoline or knife).
• Put the slices in a bowl, sprinkle with salt and toss.
• Let them sit for 10 minutes, then drain the released water.

Make the dressing

• In a small bowl, whisk the soy sauce, rice vinegar, sesame oil and sugar.
• Add the minced garlic and chili flakes and mix well.

Toss and serve

• Add the sliced red onion to the cucumbers.
• Pour the dressing over and toss until everything is well coated.
• Sprinkle with toasted sesame seeds and serve.