Grilled Tuna Rolls

Name: Grilled Tuna Rolls
Ingredients: Good olive oil; 1 pound very fresh tuna steak, 1-inch thick; Kosher salt and freshly ground black pepper; 1 lime, zest grated; 3 tablespoons freshly squeezed lime juice (2 limes); 1/2 teaspoon wasabi powder; 1 teaspoon soy sauce; 5 dashes hot sauce (recommended: Tabasco); 1 firm, ripe Hass avocado, medium-diced; 1/4 red onion, chopped; 1 tablespoon minced scallion, white and green parts; 1 tablespoon toasted sesame seeds; 9 hot dog rolls, grilled or toasted; 1 bunch baby arugula, washed and spun dry