Marinate the beef in half of the lime juice for 30 minutes.
Heat the oil in a frying pan and saute the onion until lightly browned. Set aside.
Drain the marinated beef slices and reserved the lime juice. Saute the beef in the same frying pan for 1-2 minutes on each side. Combine the remaining lime juice, soy sauce and water. Pour into the frying pan with the reserved lime juice.
Return the reserved onion rings to the pan and simmer for 1-2 minutes. Serve hot with rice.