Step 1: Prepare the cucumbers. Thinly slice the English cucumbers using a mandoline or a sharp knife. Place the slices in a bowl, sprinkle with 1/2 teaspoon of salt, and gently toss. Let them sit for 10-15 minutes to draw out excess water.
Step 2: While the cucumbers are resting, prepare the shrimp. If using raw shrimp, cook them briefly until pink and opaque, then cool and peel. If using pre-cooked, ensure they are thawed and ready.
Step 3: Make the dressing. In a small bowl, whisk together the rice vinegar, granulated sugar, and soy sauce until the sugar is fully dissolved. You can slightly warm the vinegar to help dissolve the sugar faster, then let it cool.
Step 4: Drain and combine. After 10-15 minutes, the cucumbers will have released liquid. Place them in a clean kitchen towel or paper towels and gently squeeze out as much water as possible. Transfer the squeezed cucumbers to a serving bowl along with the cooked shrimp.
Step 5: Dress and serve. Pour the prepared vinegar dressing over the cucumbers and shrimp. Toss gently to combine. Garnish with toasted sesame seeds and serve immediately, or chill for 15-20 minutes for enhanced flavor.