Place the sliced cucumbers into a mixing bowl. Sprinkle in the salt and toss to coat. Transfer the cucumbers to a colander for one hour, allowing the excess water to drain.
In the meantime, measure the soy sauce, vinegar, peanut butter, honey, garlic, dried red chili flakes, and ground black pepper into a small mixing bowl and whisk to combine.
Once the cucumbers have drained for one hour, transfer them to a bowl along with the peanuts, parsley, and sauce mixture. Toss well to coat. Serve immediately.
If making ahead of time, cover well and refrigerate for no more than 8 hours. Bring to room temperature and toss well before serving because the peanut sauce may settle at the bottom of the bowl.
