Bring a large pot of salted water to a rolling boil.

Add the trimmed green beans and cook for 3-5 minutes until bright green and tender-crisp.

Drain the beans in a colander and rinse under cold water to stop the cooking process.

In a mixing bowl, whisk together 2 tablespoons olive oil, 1 tablespoon red wine vinegar, and 1 teaspoon Dijon mustard until combined.

Add the cooled green beans, 1/4 cup finely chopped red onion, 1/2 cup halved cherry tomatoes, and 1/4 cup crumbled feta cheese; gently toss to combine.

Season with salt and pepper to taste and toss again.

Cover and refrigerate for at least 15 minutes to allow flavors to meld.

Give the salad one last gentle toss before serving and enjoy cold.