Place the cottage cheese in a fine mesh strainer over a bowl and let sit for about 15 minutes to remove any excess liquid.
In a new bowl, mix the cottage cheese with the radishes, onions, sour cream, dill, green pepper, salt, and pepper (if desired), and chill for at least 30 minutes.
Notes
Add chopped red peppers, cucumber, or celery to the salad.If desired, the radishes can be sliced instead of grated.