Rinse the cucumbers and dry thoroughly with a towel. Slice the ends off of the cucumbers, then using the flat side of a knife (you can also use a kitchen mallet or a rolling pin), smash the cucumbers with the palm of your hand along the entire length. Cut the smashed cucumbers diagonally into bite-sized pieces.
Place the cucumbers in a bowl and sprinkle with sea salt. Toss to combine and let this rest for 20 minutes to sweat.
In the meantime, make the dressing by combining soy sauce, rice vinegar, sugar, sesame oil, and garlic. Stir together.
Drain the cucumbers. Do not rinse.
Pour the dressing over the cucumbers and stir to combine. Drizzle with chili oil, if using, and sprinkle with sesame seeds and cilantro. Taste to adjust seasoning.
You can serve right away or let the cucumbers marinate for 5-10 minutes to soak up the flavors.
