Step 1

Our favorite brand of pearl couscous is Roland Israeli Couscous. For efficiency, let the shallots pickle while you prepare the remaining ingredients.

Step 2

Bring vinegar, sugar, and pinch salt to simmer in small saucepan over medium-high heat, stirring occasionally, until sugar dissolves. Remove pan from heat, add shallots, and stir to combine. Cover and let cool completely, about 30 minutes. Drain and discard liquid.

Step 3

While shallots cool, heat couscous and 1 tablespoon oil in medium saucepan over medium heat, stirring frequently, until about half of grains are golden brown, 5 to 6 minutes. Add water and ½ teaspoon salt; stir to combine. Increase heat to high and bring to boil. Reduce heat to medium-low, cover, and simmer, stirring occasionally, until water is absorbed, 9 to 12 minutes. Remove saucepan from heat and let stand, covered, for 3 minutes. Transfer couscous to rimmed baking sheet and let cool completely, about 15 minutes.

Step 4

Whisk remaining 3 tablespoons oil, lemon juice, mustard, pepper flakes, and remaining ⅛ teaspoon salt together in large bowl. Add cooled couscous, arugula, mint, peas, 6 tablespoons pistachios, ½ cup feta, and shallots and toss to combine. Season with salt and pepper to taste and transfer to serving bowl. Let stand for 5 minutes. Sprinkle with remaining ¼ cup feta and remaining 2 tablespoons pistachios and serve.