1. Place the chicken on a baking sheet or in a resealable plastic bag. Whisk together the lime peel and juice of 2 limes, orange juice, 1/4 cup of the coriander, 1 tablespoon of the garlic, and cumin. Pour the lime mixture over the chicken. Turn the chicken pieces to coat. Refrigerate for at least 1 hour and up to 4 hours. Turn at least once while marinating.
2. Meanwhile, cut the tomatoes in half lengthwise and place them cut side down on a baking sheet. Place the chillies on the baking sheet. Grill until the tomato and chilli skins are charred, turning so that all sides char. Remove from the heat and lightly cover with foil. Let stand until the vegetables are cool enough to handle.
3. Remove and discard the skins and seeds from the chillies. Finely chop and transfer them to a bowl. Peel the tomatoes and gently squeeze them to remove the seeds. Coarsely chop and add them to the bowl. Stir in the shallots, juice of 1 lime, salt, the remaining 2 tablespoons of coriander, and remaining garlic.
4. Coat a frying pan with cooking spray. Cook the onion slices over medium heat until they begin to soften, about 3 minutes. Remove the chicken from the marinade and cut into 2 cm strips. Add them to the pan and cook for about 6 minutes, or until no longer pink in the centre when tested with a knife.
5. Serve the chicken with the warm tortillas, salsa, and shredded lettuce.
Calories 322 Kilojoules 1,348 Total Fat 3 g Saturated Fat 0.5 g Sodium 450 mg Carbohydrate 53 g Dietary Fibre 8 g Protein 33 g