1. Trim off roots and leaf ends of leek. Cut leek lengthwise in half; separate into leaves. Rinse leek well with running cold water to remove all sand; drain well. Cut leek crosswise into 1/2-inch slices. Thinly slice mushrooms.
2. In 8- or 10-inch skillet over medium heat, in hot salad oil, cook leek and mushrooms until tender, stirring occasionally.
3. In bowl, beat eggs, water, and salt until blended. Reduce heat to low. Pour egg mixture over vegetables in skillet; cover and cook 15 minutes or until egg mixture is set.