Gather the ingredients.
Mix cucumbers, onion, and salt together in a bowl. Cover with plastic wrap and let sit for 15 to 30 minutes.
Turn cucumber mixture into a colander set over a bowl or in a sink. Let drain, stirring occasionally, until most of the liquid and salt has drained, 15 to 30 minutes. Transfer drained cucumber mixture to a large bowl.
Whisk mayonnaise, vinegar, sugar, dill, garlic powder, and pepper for dressing together in a bowl until smooth.
Pour over cucumber mixture and stir until coated.
Cover with plastic wrap and refrigerate for 1 to 2 hours before serving.
