01 - Bring a large pot of salted water to a boil. Add the green beans and cook for 2–3 minutes until just tender but still crisp.
02 - Drain the beans and immediately plunge them into a bowl of ice water to stop the cooking and preserve their color. Drain well.
03 - In a large bowl, combine the blanched green beans, red onion, cherry tomatoes, and parsley.
04 - In a small bowl, whisk together the olive oil, lemon juice, Dijon mustard, minced garlic, salt, and pepper until emulsified.
05 - Pour the dressing over the salad and toss gently to combine.
06 - Sprinkle the crumbled feta over the salad just before serving.