Yellowfin Tuna Escabeche

To prepare tuna: In a small, dry skillet, over medium heat, combine sesame seeds and peppercorns. Allow to heat until the sesame seeds are toasted, about 30 seconds to 1 minute. Transfer to a spice grinder and pulverize until not quite finely ground. Place in a small bowl and mix well. Cut tuna into 1-inch by 3- to 4-inch lengths. Place these blocks of tuna in a wide shallow dish. Rub lightly with ground spice mixture. Cover and refrigerate for at least 30 minutes or as long as 2 hours. Remove tuna from refrigerator and set aside to bring to room temperature.

To prepare escabeche: In a large nonstick or well-seasoned skillet over a high flame, heat peanut oil until it begins to smoke. Immediately add tuna blocks and sear each one for 15 seconds on each side. Transfer seared tuna to a wide shallow dish, and allow cooling. Combine marinade ingredients in a mixing bowl, add tuna, and soak well by covering and refrigerating for 1 to 3 hours, depending on the thickness of the fish, and turn once.

To prepare vinaigrette: In a small pan over high heat, bring the orange juice to a boil and reduce to ½ cup. Transfer to a medium-size mixing bowl, add the vinegar, and whisk to blend. Add the extra virgin olive oil, shallots, and black pepper and salt to taste. Whisk to combine, and set aside.

To serve, remove seared tuna from marinade and slice into 1/8-inch pieces. Spoon a pool of vinaigrette onto each plate. Divide slices onto plates. Arrange with the orange segments and avocado slices. Serve immediately.