Turkey Burger with Wasabi Mayo

Name: Turkey Burger with Wasabi Mayo
Ingredients: 2 1/4 pounds ground turkey; 6 scallions (white and green parts), finely chopped; 3 tablespoons soy sauce; 1 tablespoon mirin; 1 1/2 teaspoons dark sesame oil; 1 teaspoon kosher salt, plus additional for seasoning; Vegetable oil, for brushing; Freshly ground black pepper; 6 sesame seed hamburger buns; 1 1/2 ripe Hass avocados, halved, pitted and thinly sliced; 6 slices ripe tomato; 1 1/2 cups alfalfa sprouts; 13 cup pickled ginger; 4 teaspoons water; 4 teaspoons wasabi powder; 1/2 cup mayonnaise