Soak the onions:
Place the chopped onions in a small bowl of water. This will help take the edge off the onions. Let sit while you prepare the rest of the salad.
Blanch the green beans:
Bring a large pot of salted water to a boil (2 tablespoons of salt for 2 quarts of water). Add the green beans to the water and blanch only for about 2 minutes or so, until the beans are just barely cooked through, but still crisp.
Fresh young beans should cook quickly. Older, tougher beans may take longer.
Shock in ice water:
While the beans are cooking, prepare a large bowl of ice water. When the beans are ready, use a slotted spoon to remove them from the boiling water to the ice water to stop the cooking.
Drain the green beans and the red onions.
Here’s a tip. Green vegetables when cooked for seven minutes or longer, or exposed to acid like lemon juice or vinegar, will turn a drab olive color.
