Avocado and Curried Tuna Salad

Name: Avocado and Curried Tuna Salad
Ingredients: 2 ripe Hass avocados, halved (see Note); 1 cup finely diced peeled tart apple; 2 tablespoons finely chopped dill; 1 small onion, finely diced; 2 celery ribs, finely diced; 1 large scallion, thinly sliced; 2 teaspoons freshly squeezed lemon juice; 3/4 teaspoon curry powder; 1/2 cup plus 2 tablespoons mayonnaise; 2 6-ounce cans water-packed albacore tuna, drained; Salt and freshly ground pepper; 2 cups arugula leaves (lightly packed); 2 medium tomatoes, cut into 1-inch dice