Grilled Tuna Nicoise Sandwich

Name: Grilled Tuna Nicoise Sandwich
Ingredients: 1.5 ounces green beans; 1 tablespoon minced shallot, divided; 300 grams piece of fresh tuna; 1 small potato scrubbed well; 2 teaspoons dry white wine; boston lettuce leaves; sliced tomato; 1 boiled egg; 1 teaspoon olive oil, plus more for grilling; 0.75 teaspoons lemon juice, divided; 0.5 teaspoons dijon; 2.5 tablespoons mayonnaise; 1 tablespoon pitted, chopped nicoise olives; 1 anchovy fillet, chopped finely; 0.5 tablespoons chopped capers; sea salt and freshly ground pepper; thick slices of a crusty, dense bread of choice