In a bowl, combine the tuna, shallots, chives, orange zest, 1 1/2 tablespoons of the olive oil, verjus, salt, and pepper.
Arrange the arugula on 4 salad plates. Lightly drizzle with some verjus and olive oil. Place 3-inch ring-mold in the center of the arugula and mound the tuna tartare into the mold. Remove the mold. Sprinkle each serving with chopped walnuts and drizzle with the remaining olive oil.
Wine Pairing: Louis Jadot Beaujolais-Villages, France, most current vintage available
Yield: 4 servings