Add the rice vinegar, sesame oil, grated ginger, soy sauce, and sugar to a small bowl. Whisk until combined and set aside.
Place the cucumbers on a cutting board. Gently smash each cucumber using the smooth side of a meat mallet, rolling pin, or jar until the sides crack open.
Cut the smashed cucumbers into rough 1-inch pieces and transfer them to a large bowl.
Sprinkle with salt, toss well, and let stand for 20 minutes.
Drain the excess cucumber liquid from the bowl.
Add the cilantro, green onions, and sesame ginger dressing.
Toss well and serve immediately.