Tomato and red onion salad

1 med red onion in 1/4" slices
1/2 c. cider vinegar
1/4 c sugar
8 c tomatoes, use a variety

1. let onions soak in 4 c. cold water and 2 t. salt for 20 min; drain.
2. Whisk vinegar, sugar, and 3/4 t. salt and fresh ground pepper.
3. Combine onions, dressing, and tomatoes.