Step 1

Bring a large pot of water to a boil over high heat and season with a large pinch of salt. Add the green beans and cook for 3 to 4 minutes until tender but still crisp. Transfer to a boil of iced water to cool and then drain and pat dry.

Step 2

Add the green beans, onions, and walnuts to a large bowl.

Step 3

In a separate bowl, whisk together the vinegar and olive oil. Season with salt and pepper, to taste.

Step 4

Pour the vinaigrette over the green beans, onions, and walnuts and toss to combine. Transfer to a platter and top with crumbled feta and freshly cracked black pepper.