In a clean 1-quart glass jar combine vinegar, chives, chopped onion, and lemon peel strips. Cover with plastic wrap and refrigerate for I week, stirring once a day. Pour the vinegar-chive mixture through a fine-mesh strainer and let it drain into a bowl. Discard solids.
Transfer strained vinegar to a clean 1-quart jar or bottle. Add whole green onion to the jar or bottle. Cover tightly with a nonmetallic lid (or cover with plastic wrap and tightly seal with a metal lid). Store vinegar in refrigerator for up to 6 months.