Prepare Ice Bath: Fill a bowl with ice water and set it aside.

Blanch Green Beans: Boil water in a large pot, then add the green beans. Cook for 1-2 minutes.

Cool Green Beans: Transfer the green beans to the ice bath to halt cooking. Drain well once cooled.

Cook Potatoes: In the same pot, boil the small white potatoes for 15-20 minutes until fork-tender.

Drain and Cool Potatoes: Drain the cooked potatoes and let them cool slightly.

Make Vinaigrette: Whisk together balsamic vinegar, Dijon mustard, minced garlic, and salt. Drizzle in olive oil while whisking.

Combine Ingredients: Slice cooled potatoes in half and place them in a bowl with the green beans.

Dress the Salad: Drizzle vinaigrette over the mixture, tossing gently to coat.

Garnish and Serve: Add chives and serve at room temperature.