Cook the green beans in a pan of boiling water for 3 mins, drain and keep warm. Meanwhile, toss together the chicken livers, olive oil and rosemary.
Heat a large non-stick pan and cook the chicken livers over a high heat for 5-6 mins until nicely browned and cooked through they should still be a little pink in the centre.
Arrange the beans on serving plates with the lettuce leaves and watercress.
Add the vinegar to the pan, cook for a couple of seconds then spoon over the salad.
