Bring a large pot of heavily salted water to a boil. Make a large ice bath by placing ice and very cold water in a large bowl.
Add olive oil, chives, salt, pepper, lemon zest, and lemon juice to a mixing bowl. Whisk together well until combined. Cover, and place in the fridge until it's time to dress the salad.
Once the salted water is boiling, place the beans into the boiling water, and cook for about 3-5 minutes. You want the green beans to become a vibrant green color while also maintaining their crisp texture. Once the beans are cooked to your liking, immediately add them to a large bowl of cold water and ice to stop the cooking process.
To avoid a watery salad, make sure to remove the green beans from the ice water bath as soon as they are completely chilled using a skimmer. Place some paper towels at the bottom of the bowl to catch any excess water, and use paper towels to dry off the beans.
Now, pour the dressing over the beans and toss to combine. Next, crumble on the feta cheese. Toss again, adjust the seasonings according to your tastes, then plate with more lemon, chives, salt, and pepper. Enjoy!
Store in an airtight container in the fridge for 3-5 days. Do not freeze.