Slice the cucumbers into thin rounds about 1/8 inch thick. Place them in a colander, toss with 1 teaspoon of kosher salt, and let them drain for 10 minutes over the sink. This keeps the brine from getting watery. After 10 minutes, rinse lightly and pat dry with a clean towel.

While the cucumbers drain, bring a small saucepan of water to a boil. Fill a large bowl with cold water and a generous handful of ice cubes and set it nearby. Drop the snap peas into the boiling water for exactly 30 seconds, then immediately scoop them out and drop them into the ice water. Leave them there for 2 minutes. This quick blanch and shock keeps them bright green and extra crisp even after pickling. Drain them well and pat dry.

In the same small saucepan, combine the rice vinegar, water, sugar, and 3/4 teaspoon of kosher salt. Set it over medium-low heat and stir for about 1 to 2 minutes just until the sugar and salt dissolve completely. Remove from heat. You do not need to bring it to a full boil. Let it cool for 5 minutes, then stir in the sesame oil if using.

Combine the dried cucumber slices and blanched snap peas in a quart jar or a large mixing bowl. Pour the cooled brine over the vegetables and stir gently to coat everything evenly. The brine should just barely cover or sit right at the level of the vegetables.

Cover the jar or bowl and refrigerate for at least 1 hour before serving. For a fuller flavor, let it sit for 2 to 3 hours. When ready to serve, give the jar a gentle shake or stir the bowl, then spoon the salad into a serving dish. Scatter sesame seeds over the top if using. Taste and add a small pinch of salt if needed.