For the dressing mix all the ingredients together well and allow to infuse. For the salad mix the olives, onions, tomatoes, cucumber, and pine nuts together. Toss half of the dressing through the salad ingredients. Toss the herbs, lemon juice and zest and cumin with the potatoes.
Spread half the lettuce out on a serving platter followed by a layer of potatoes and a layer of the salad ingredients. Continue until you've used up all the ingredients and arranged it nicely. Drizzle with the remaining dressing and serve with crusty toasted ciabatta.