Preheat oven to 350 degrees. Make 2 lengthwise slits in leek and rinse it in a bowl of water. Arrange leeks in a gratin pan. In a sauce pan combine water, olive oil, marjoram, cinnamon, red wine vinegar, oregano and salt to taste. Bring liquid to a boil and simmer 10 minutes. Pour liquid over leeks to just cover. Arrange a piece of foil over dish and bake 35 minutes, or until tender. Transfer leeks to a serving plate. Reduce cooking liquid to 1/2 cup and strain over leeks. Chill, covered, 2 hours or overnight. Before serving, garnish with tomatoes, olives, cheese and fresh herbs.