Prep the veggies: Slice 1 large English cucumber and 1/2 small red onion thinly. Place the cucumber slices in a colander.
Salt the cucumbers: Toss the cucumber slices with 1 teaspoon of salt and let them rest for 30 minutes to drain.
Dry the cucumbers: Gently pat the cucumber slices completely dry with paper towels to remove all remaining moisture.
Make the dressing: In a large bowl, whisk together 1 cup sour cream, 1/4 cup mayonnaise, 2 tablespoons dill, and 1 tablespoon vinegar. After, stir 1 teaspoon sugar, 1/2 teaspoon garlic powder, and 1/4 teaspoon black pepper into the dressing until smooth.
Combine and chill: Add the dry cucumber and red onion slices to the dressing. Stir gently to coat, then chill for 30 minutes.
