Place sliced cucumbers in a large nonreactive bowl. Sprinkle with kosher salt and toss to coat. Let sit for 30 minutes to draw out moisture. Drain and discard excess liquid.
In a separate nonreactive bowl, combine rice vinegar, fish sauce (or soy sauce), garlic, ginger, and Korean chile powder. Mix well.
Add drained cucumbers to the dressing and toss until well coated.
Transfer the mixture to a resealable nonreactive container. Cover and refrigerate for at least 12 hours to allow flavors to develop.
Serve chilled as a side dish or with rice and grilled meats.
