Preheat oven to 375 degrees. Spread pine nuts on a rimmed baking sheet; toast in oven, shaking once, until golden and fragrant, 10 minutes. Transfer to a plate to cool.
With a vegetable peeler, peel 8 long pieces of zest from orange; cut lengthwise into very thin strips. Halve orange; squeeze 2 tablespoons juice into a medium bowl (reserve unused portion for another use). Add vinegar, onion, and salt; let stand 10 minutes. Add capers, olives, parsley, pine nuts, and zest to bowl. Season with pepper; toss thoroughly with oil. Divide among six plates.