Meanwhile, prepare an ice water bath. Bring a small pot of water to a boil. Add the eggs and return to a boil, then boil for 7 minutes. Immerse the eggs in the ice water bath until completely cool, then peel and transfer to a medium bowl. Lightly mash the eggs with a large fork. Gently stir in the chives, vinegar and the remaining 1 tablespoon of olive oil. Season with salt and pepper.