Slice the English cucumbers into thin rounds and place them in a colander. Sprinkle a generous amount of salt over the cucumbers and toss gently. Let sit for 30 minutes to an hour.

Rinse the cucumbers under cold water to remove the salt, then gently press with a clean kitchen towel or paper towels to absorb any remaining moisture.

In a mixing bowl, combine sour cream, everything bagel seasoning, white vinegar, and black pepper. Whisk until smooth and creamy.

Add the drained cucumbers and thinly sliced red onion to the dressing. Toss gently to ensure each cucumber slice is coated.

Cover the salad and refrigerate for at least 30 minutes before serving.