Green Bean and Cherry Tomato Salad

This one was such a winner. I want to send a HUGE thank you to Smitten Kitchen for this delicious and healthy side dish idea. I served it alongside baked ziti and home made bread. The bread with the salad was delicious. I used it to soak up all the extra dressing. If I was not serving with a crusty bread, I would likely halve the dressing recipe, because it was far too much dressing for JUST the veggies. So great and easy, you have to try it!
I am submitting this wonderful recipe to Joelen's Tasty Tools roundup because you need your whisk to get the dressing right. I reccomend using a very small whisk because of how little you need to mix up.
Green Bean and Cherry Tomato Salad

1 pound green beans
1 pound cherry tomatoes
1/4- 1/2 an onion
2 tablespoons red wine vinegar
Salt and pepper
1/3 cup extra-virgin olive oil

Top and tail the beans (I also halve the big ones at this stage), and parboil them in salted water until tender (2-4 min). Drain and immediately spread them out to cool. Stem the cherry tomatoes and cut them in half. Can do up to here in advance, but do not move ahead before you are ready to eat.

For the vinaigrette, dice the onion fine and put it in a bowl with the vinegar and salt and pepper. Whisk in the olive oil. Taste and adjust the balance with more vinegar, oil, or slat, as needed. Toss the cherry tomatoes in with the vinaigrette; this can sit for a while. Do not add the green beans until just before serving or they will discolor. Toss and serve.