Place chicken breast in a pot with enough chicken stock to cover, bay leaf and half an onion and boil.
Cook until the chicken is easy to shred, about 35 minutes. Remove from heat and strain. Shred chicken and then set aside.
Combine orange juice, lime juice, salt, black pepper, garlic, oregano, cumin and olive oil.
Place a large frying pan over high heat. Add shredded chicken and mojo sauce and cook until the sauce has evaporated. Add sliced onions and bell pepper and fry until chicken is crispy about 2-3 minutes. Remove from heat and serve warm.