1/4 cup rice vinegar1 tablespoon lemon juice from 1 small lemon
2 tablespoons toasted sesame oil
2 teaspoons granulated sugar
1/8 teaspoon red pepper flakes, plus more to taste
1 tablespoon sesame seeds, toasted in a pan over medium heat until fragrant and golden, 4 to 5 minutes
3 medium cucumbers, sliced, salted, and drained (see directions)
Peel, halve lengthwise, and scoop seeds from cucumbers. Stack halves flat side down; slice diagonally 1/4-inch thick. Toss with 1 tablespoon salt in strainer or colander set over bowl; weight with water-filled, one-gallon-sized zipper-lock freezer bag, sealed tight. Drain for at least 1 hour, and up to 3 hours. Transfer to medium bowl; reserve for further use.
Whisk all ingredients except cucumbers in medium bowl. Add cucumbers; toss to coat. Serve chilled or at room temperature.