Peel 2 long English cucumbers and score the outside by running a fork down the length of each cucumber several times.
Slice the cucumbers into ¼-inch slices and place them in a large mixing bowl.
Thinly slice ½ red onion and add it to the bowl with the cucumbers.
In a small bowl, whisk together ½ cup sour cream, ½ cup fresh chopped dill, 2 Tbsp white vinegar, 1 tsp sugar, ½ tsp salt, and ¼ tsp garlic powder until smooth.
Pour the dressing over the cucumbers and red onion. Toss gently until everything is evenly coated.
Cover and refrigerate for 1 hour.
Serve chilled.
Notes
Refrigerate the leftovers in an air tight container for up to 3-4 days.