Whisk together oil and vinegar.
While the boiled vegetables and kidney beans are still slightly warm, pour the vinegarette over them, toss, cover, and let stand for approximately 15 minutes (they should absorb most of the dressing).
Add the remaining ingredients, season to taste, and mix well.
Cover and chill before serving. Serve garnished with torn lettuce leaves.
Vinegret is not runny and will keep well in the refrigerator for up to 36 hours.