In a large heatproof bowl, stir the couscous with ¾ cup of boiling water. Cover with a lid and steam for 5 minutes. Fluff with a fork.
Meanwhile in a nonstick skillet heat 2 tablespoons of the oil. Add the shrimps and crushed red pepper and cook over medium high heat until golden, 3 minutes. Transfer to a plate.
Add the butter to the skillet, then the beans, capers and lemon juice and cook, stirring for 2 minutes.
Fold the beans mixture, parsley and remaining 1 tablespoon of olive oil in the couscous, season with salt and pepper to taste.
Serve topped with the shrimps, squeeze a drizzle of lemon juice over the entire dish.