1.Wash the cucumber and pat dry. Make the salad dressing by combining the salt, sugar, sesame oil, soy sauce, and rice vinegar. Stir until the sugar and salt are completely dissolved. Set aside.
2.On a cutting board, lay a large knife flat against the cucumber, and smash it lightly with your other hand. The cucumber should crack open and smash into four sections. Repeat along its full length. Once the whole cucumber is completely open, cut it at a 45-degree angle into bite-sized pieces.
3.In a large bowl, mix the cut cucumber with the prepared dressing, garlic and chili oil, and toss it well. Serve, garnished with sesame seeds and cilantro.