In a large pot, heat 2 quarts of water to a boil. Add 1 tablespoon of olive oil and a pinch of salt. Add the couscous and stir. Lower the heat to medium, and cook until al dente, about 4 to 6 minutes. Drain, reserving 1 tablespoon of cooking water.
Return the couscous to the pot, and drizzle with 4 tablespoons olive oil and the reserved tablespoon of water. Mix well with a rubber spatula, and pour out onto a rimmed baking sheet. Let cool for 10 minutes, stirring the couscous after 5 minutes to prevent clumping.
In a large bowl, combine the couscous, sugar snap peas, preserved lemons, mint, 2 tablespoons olive oil, and the lemon juice. Toss gently with a spatula, to avoid bruising the mint. Season to taste with salt and pepper (the feta will increase the salt content, so go easy).
Gently fold the feta into the salad, so the cheese doesn’t fall apart. Taste for seasoning and add more lemon juice, if needed. Serve in a large bowl, garnished with parsley. (If prepared several hours ahead and chilled, remove from the refrigerator 15 minutes before serving.)