Wash the spinach very well. Remove the stems. Shake the leaves to remove any surplus water & then pat dry with paper towels (or spin in a lettuce spinner). Tear the leaves into large pieces & arrange on a shallow dish. Sprinkle with the salt, stir in thoroughly & leave to stand for 15 minutes. Drain & squeeze dry. Place the spinach in a bowl. Chop the green onions finely & sprinkle in the bowl. Mix together the oil & lemon juice & pour into the bowl. Toss lightly & sprinkle with chopped walnuts.