Rub salmon with harissa, olive oil, lemon juice, salt, and pepper.

Bake at 400F for 10-12 minutes, until just cooked through.

Bring broth to a simmer, stir in couscous, cover, and remove from heat for 5 minutes.

Fluff couscous with a fork, then fold in cucumber, tomatoes, parsley, and lemon zest.

Serve salmon over couscous with extra lemon.