1. Bring 1 1/2 cups water to a boil in a small pot. Put the couscous and peas in a large bowl and pour the water over them. Stir once and then cover the top of the bowl with aluminum foil. Set aside to steam for 5 minutes.
2. Uncover the bowl, fluff with a fork and set aside to cool, about 10 minutes. Toss in the prosciutto, mint, lemon juice, olive oil, lemon zest, 1 teaspoon salt and 1/4 teaspoon pepper. Season with additional salt and pepper if needed. Serve at room temperature.