Shake oil, vinegar, lemon juice, garlic and peppercorns in tightly covered large jar.
Add olives; cover and shake to coat olives evenly with liquid.
Refrigerate at least 8 hours, tipping jar occasionally to distribute marinade.
About 5 hours before serving, wash tomatoes and drain.
Cut each in half; add to marinade in jar.
To serve, remove vegetables with slotted spoon.