1 1/2 pounds small new potatoes, boiled until tender and cooled
1/2 pound green beans, trimmed, boiled until tender and cooled
1 cup halved cherry tomatoes
1/2 cup pitted Niçoise olives
1/2 cup thinly sliced red onion
1 hard boiled egg, peeled and cut into wedges(optional)
How to make it
In a small bowl, whisk together vinegar, tarragon, Dijon, shallot, salt and pepper. Slowly whisk in oil to make a vinaigrette. Put tuna into a wide, shallow dish, drizzle all over with 2 tablespoons of the vinaigrette, cover and chill for 30 minutes.
Spray grill with cooking spray and preheat to medium heat. Grill tuna until cooked to desired doneness, 5 to 7 minutes on each side; transfer tuna to a plate. When cool enough to handle, flake into large pieces. Arrange tuna, potatoes, green beans, tomatoes, olives, onion and egg (if using) on a large platter and serve with remaining vinaigrette on the side to spoon over the top.