1. Generously salt the cucumber and marinate for 15 minutes at room temperature.
2. Pick the mint and parsley leaves and chop. Squeeze the juice from the lemon.
3. In a colander, rinse and drain the cucumber.
4. In a large bowl, combine the cucumber, mint, parsley, lemon juice, yogurt, and piment d'Espelette. Season to taste with salt. Cover and refrigerate until cold (at least 1 hour). Serve with toasts.