Step 1: Prepare the Cucumbers
Wash the cucumbers thoroughly. If using English cucumbers, you can leave the skin on (it’s thin and tender). If using regular cucumbers, peel them and slice in half lengthwise to scoop out the seeds with a spoon. Using a sharp knife or mandoline, slice the cucumbers very thinly – about ⅛ inch thick or thinner. The thinner the slices, the better they’ll absorb the dressing.

Step 2: Salt and Drain
Place the sliced cucumbers in a colander set over a bowl or in the sink. Sprinkle with 1 teaspoon of salt and toss to distribute evenly. Let sit for 15-20 minutes. This process draws out excess moisture that would otherwise dilute your dressing and make the salad watery. You’ll see liquid collecting in the bowl – this is exactly what you want.

Step 3: Drain and Dry
After 15-20 minutes, rinse the cucumbers briefly under cold water to remove excess salt. Drain well, then pat completely dry with paper towels or a clean kitchen towel. Getting the cucumbers as dry as possible is important for the best texture and prevents a watery salad. Take the extra time to thoroughly dry them.

Step 4: Make the Dressing
In a medium bowl, whisk together the sour cream, vinegar, sugar, fresh dill, salt, pepper, and garlic (if using). Whisk until smooth and well combined. The sugar should dissolve completely. Taste the dressing – it should be tangy, slightly sweet, and well-seasoned. Adjust any element to your preference at this stage.

Step 5: Combine
Place the dried cucumber slices in a large mixing bowl. If using red onion, add the thinly sliced onion now. Pour the creamy dressing over the cucumbers and toss gently but thoroughly to coat every slice. Make sure the dressing is evenly distributed and all cucumber slices are coated.

Step 6: Chill
Cover the bowl with plastic wrap or transfer to an airtight container. Refrigerate for at least 2 hours before serving, or up to 24 hours. This chilling time allows the flavors to meld together and the cucumbers to absorb the dressing. The salad actually tastes better after sitting – the flavors develop and deepen.

Step 7: Serve
Before serving, give the salad a gentle stir. If it looks a bit watery (cucumbers release some moisture over time), drain off any excess liquid. Taste and adjust seasoning if needed – you might want to add a pinch more salt or a splash more vinegar. Garnish with additional fresh dill if desired and serve cold.