Vision: Seeing an onion: tears and sorrow. Peeling an onion: slowly mysteries are being uncovered. Eating cooked onions: have courage—a small unpleasant affair is resolved.
Depth Psychology: The onion is a sign that after a period of depression things are beginning to improve. Tears are there to wash the pain from the soul. As an aside: in ancient Egypt, onions and garlic were worshiped like gods.