Slice the cucumber in half, lengthwise. Place the cucumber, cut side facing down, and smash it, applying pressure with the back of a knife against the cucumber or smacking it until it starts to split. Then slice the cucumber into small pieces of 1 cm.
In a small bowl mix soy sauce, rice vinegar, sugar, chili flakes, sesame oil, and 1 tsp of water. If necessary, add salt to taste.
Fill two small mason jars with the cucumber and edamame. Add dressing, mix and top with sesame seeds and chopped cilantro.
Eat immediately or put a lid on and reserve until ready to be consumed.