Salad Nicoise with Seared Tuna

Name: Salad Nicoise with Seared Tuna
Ingredients: 2 garlic cloves, minced; 1 teaspoon Dijon mustard; 3 tablespoons red wine vinegar; 1/2 lemon, juiced; 2 tablespoons chopped fresh flat-leaf parsley; 2 tablespoons minced fresh tarragon; Sea salt and freshly ground black pepper; 1/2 cup extra-virgin olive oil; 1 pound small red new potatoes, scrubbed and halved; 8 large eggs; 1/2 pound haricots verts or French green beans, stems trimmed; 2 pounds fresh sushi-quality tuna; 2 tablespoons extra-virgin olive oil; 1 pint teardrop or cherry tomatoes, halved; 1 cup nicoise olives; 16 anchovy fillets; 16 caper berries with stems; 1/2 bunch fresh chives, snipped in 1/2