1Combine orange juice, lime juice, oil, spices, and cilantro in a shallow dish. Add the fish, turning to coat. Let marinate 15 minutes.
2Meanwhile, in a small saucepan over medium heat bring to onion, vinegar, jalapeno, and sugar to a boil. Immediately remove from heat; let cool. Discard jalapeno.
3Heat the grill to high. Cook the fish over indirect heat for 8 minutes, or until cooked through. Pull apart into large flakes. Cook the tortillas over direct heat for 20 seconds on each side, until soft and slightly charred in places.
4To assemble tacos, spoon chicken onto center of each tortilla; top with pickled onions and salsa verde. Fold sides of tortilla over filling. Serve with lime wedges.