Combine the couscous with the boiling water in a large heatproof bowl, cover; stand for 5 minutes or until the water is absorbed, fluffing with the fork occasionally.
Toast the pine nuts in a heated dry pan. Cool off.
Add the olive oil and the lemon juice, the grated peel and gently mix. Fold the spinach and the pine nuts in the couscous and season with salt and pepper.