In a large bowl, combine the sliced cucumbers and salt. Toss to coat and let sit for about 15 minutes to draw out excess moisture.
In a separate bowl, whisk together the rice vinegar, soy sauce, sesame oil, sugar, minced garlic, and grated ginger until the sugar is dissolved.
After 15 minutes, drain any excess liquid from the cucumbers and pat them dry with paper towels.
Pour the dressing over the cucumbers and toss to combine. Add the sesame seeds and green onions, mixing gently.
Let the salad sit for at least 10 minutes before serving to allow the flavors to meld. Garnish with fresh cilantro if desired.