Wash and dry 1 pound Persian cucumbers thoroughly. Slice into uniform 1/4-inch rounds using a sharp knife or mandoline.
Place cucumber slices in a large bowl and sprinkle with 1 teaspoon kosher salt. Toss gently to coat all pieces evenly. Let sit at room temperature for 15 minutes to draw out excess moisture.
Transfer cucumbers to a colander and rinse briefly under cold water to remove excess salt. Drain well, then pat completely dry with clean kitchen towels or paper towels.
In a separate mixing bowl, combine 2 sliced green onions, 1 tablespoon rice vinegar, 1 tablespoon soy sauce, 1 teaspoon maple syrup, 1 tablespoon gochugaru, 1 teaspoon toasted sesame oil, and 1 teaspoon minced garlic. Whisk together until well blended.
Add the dried cucumber slices to the dressing bowl and toss gently but thoroughly, making sure every piece gets coated in the dressing. Taste and adjust seasoning if needed.
Transfer to a serving bowl and sprinkle with 1 teaspoon toasted sesame seeds. Serve immediately at room temperature or chill in the refrigerator for 10-15 minutes before serving.