CHILE-CRUSTED TUNA TACOS

Steps:

• Bring orange juice, chipotles, and vinegar to a boil in a 1- to 1 1/2-quart heavy saucepan, then reduce heat and simmer, stirring occasionally, until reduced to a generous 1/3 cup, 15 to 20 minutes. Remove from heat and cool.
• While sauce cools, prepare charcoal or gas grill for cooking. If using a charcoal grill, open vents on bottom of grill, then light charcoal. Charcoal fire is medium-hot when you can hold your hand 5 inches above rack for 3 to 4 seconds. If using a gas grill, preheat burners on high, covered, 10 minutes, then reduce heat to moderately high.
• While grill heats, stir together coriander, cumin, chili powder, black pepper, and kosher salt in a shallow bowl. Brush tuna on all sides with 1 tablespoon oil (total), then coat all sides evenly with spice mixture.
• Grill tuna on lightly oiled rack, uncovered, turning to brown all sides, until browned on outside but still rare in center, 8 to 10 minutes total. Let tuna stand 10 minutes.
• While tuna stands, heat tortillas on grill, turning over once, until warm, about 1 minute, and keep warm, wrapped in foil.
• Toss jicama with cilantro, lime juice, remaining tablespoon oil, and salt and pepper to taste in a small bowl. Halve, pit, and peel avocado, then cut into 1/2-inch-thick slices.
• Put a tortilla on each of 4 plates. Divide arugula, jicama, and avocado among tortillas, arranging evenly down center of each. Slice tuna 1/4 inch thick and divide among tacos. Drizzle chipotle sauce evenly over tuna and roll up tacos to enclose filling.