Start by rinsing a large English cucumber under cool water, then slice it in half lengthwise. Cut each half into half-moon shapes about ¼ inch thick and place in a large mixing bowl.

Next, thinly slice a red onion into rings and add it to the bowl with the cucumbers. Finely chop fresh dill and sprinkle over the cucumbers and onions.

In a medium bowl, combine sour cream, lemon juice, and garlic powder. Add salt and pepper to taste and mix until creamy.

Gently pour the dressing over the cucumber and onion mixture, folding everything together until well-coated.

Cover the bowl with plastic wrap or transfer to an airtight container and chill in the refrigerator for at least 1 hour.