- Place the chicken breasts in a dish and sprinkle with the lime juice. Cover and marinate for up to 12 hours.
- When ready to cook, preheat the oven to 140°C, 300°F, Gas Mark 1.
- Stack the tortillas, wrap in aluminum foil and place in the oven to warm through.
- Heat the olive oil in a large frying pan, add the onion, and garlic and sauté for 5 minutes, or until just tender.
- Meanwhile, cut the chicken into 6mm/1/4-inch pieces.
- Stir in the chicken pieces into the frying pan, season with the cumin, salt, and black pepper and cook for 5 minutes, stirring from time to time minutes, until the chicken is opaque and cooked through.
- Add the chopped tomato, coriander and the lemon juice, mix well then remove from the heat and transfer to a warm serving dish.
- To serve - Stack 2 tortillas (to prevent tearing) and place the chicken, salsa, lettuce on the tortilla stack. Roll it up and lick your fingers.