How to Make It
In a mortar, combine the garlic, lemon zest, peppercorns and a pinch of salt and mash to a coarse paste. Stir in the lemon juice and then 1/4 cup of the oil.
In a large skillet, heat the remaining 1 teaspoon of oil. Add the shrimp and cook over moderately high heat, stirring, until beginning to curl, about 3 minutes. Add the arugula and stir until wilted and the shrimp is cooked through, about 2 minutes. Add the olive oil mixture, toss well and season with salt; serve hot.