Capers, the pickled flower bud of a bush that grows in the Mediterranean region, add a piquant note to this salad. For greatest impact, stir in the capers immediately before serving.
Spinach grows in sandy soil and tends to be gritty unless you buy it prewashed. Soak the leaves in a large bowl of cold water for at least 10 minutes, then lift them into a colander to drain, leaving the grit behind in the bowl. Rinse the bowl and repeat the soaking process until no trace of sand remains when you lift out the leaves.