1. Peel the oranges to remove the skin and white pith. Slice the oranges into thin rounds over a bowl to collect the juice.

2. In the bowl, mix the collected juice with the lemon juice, mustard, a pinch of salt, and pepper. Pour in the oil in a thin stream while whisking to emulsify.

3. Rinse and dry the lettuce. Chop the onions and fennel. Drain and rinse the chickpeas.

4. Arrange the lettuce leaves in bowls. Add the orange slices, fennel, drained chickpeas, olives, and chopped onions. Drizzle with the vinaigrette and serve.