Combine flour and pepper. Coat chicken with flour mixture (shake off excess.) Spray a 10 inch skillet with cooking spray for 2 seconds; over medium heat, lightly brown chicken on both sides. Combine lemon juice, garlic, Worcestershire and hot pepper sauce; pour over chicken. Cover; simmer for 15 minutes or until chicken is done. Sprinkle walnuts and cheese over chicken. Arrange lettuce on sandwich rolls; top with chicken. Serve immediately.