Pinzimonio with Tonnato Sauce

Name: Pinzimonio with Tonnato Sauce
Ingredients: 1/4 cup extra-virgin olive oil, plus more for drizzling; One 8-ounce jar Italian tuna in olive oil, drained; 3 tablespoons fresh lemon juice; 4 oil-packed anchovies, drained; 2 tablespoons capers, rinsed; 1/4 cup mayonnaise; 1/4 pound green, Roma or wax beans; 8 Parisian round carrots or baby carrots; 4 tender celery ribs with leaves attached, quartered crosswise; 2 lemon, Persian or Kirby cucumbers, peeled and quartered lengthwise; 2 small watermelon radishes, cut into 8 wedges each, or 10 small radishes, halved; 1 fennel bulb, cored and cut into 16 wedges; 1/2 teaspoon coarse sea salt