How to Make It
Using a Y-shaped vegetable peeler, remove peel from lemons, leaving the white pith. Place peel strips in a bowl. Using a small, sharp knife, remove and discard pith. Cut lemons into 1-inch pieces, and place in bowl with peel strips. Rub salt into lemon mixture until sandy. Cover and chill 8 hours or overnight.
Process lemon pieces, yogurt, and ginger in a blender until smooth. Transfer to an airtight container, and chill until ready to serve.
Arrange lettuce, cucumber, onion, and olives on a large rimmed platter.
Heat a small skillet over medium. Add cumin seeds, and cook, stirring often, until toasted and fragrant, about 1 minute.
Drizzle salad with some of the yogurt dressing, and sprinkle with toasted cumin. Serve immediately with remaining dressing.