For vinaigrette dressing, in a blender container, combine Basil Vinegar, basil, orange juice, and mustard. Cover and blend well.
With motor running, pour olive oil through top of blender container. Blend until well mixed. Transfer to a non-metal container. Cover and chill, if you like.
For salad, line platter or individual plates with greens. Overlap orange slices on greens. Sprinkle onion over fruit. Drizzle with vinaigrette. Sprinkle chives and pepper over salad. Makes 4 side-dish servings.
In a non-metal container, place white vinegar or white wine vinegar and fresh basil. Cover and let stand in a cool, dark place for 24 hours.