This recipe is super-versatile—just about any green that's hanging out in your crisper can be whirred into the garlicky sauce, and you can swap plums for the peaches and quinoa for the couscous.
To prepare chicken: Pulse garlic in a food processor until chopped. Add greens and pulse until chopped. Add oil, red-wine vinegar, crushed red pepper and salt; pulse until combined but not pureed. Divide the sauce into three 1/3-cup portions.
Thread chicken onto 4 skewers. Baste both sides with 1/3 cup sauce. Set in a baking dish or on a plate. Cover and refrigerate for at least 30 minutes and up to 1 day.
Meanwhile, prepare pickled peaches: Combine white vinegar, water, sugar, cardamom, cloves, cinnamon stick and ginger in a small saucepan. Bring to a boil over high heat. Cook, stirring occasionally, until the sugar is dissolved. Place peaches and onion in a wide-mouth mason jar or large nonreactive bowl. Pour the vinegar mixture over them. (Make sure the peaches and onion are completely submerged.) Set aside to cool to room temperature.
Preheat grill to medium-high.
Bring water to a boil in a small saucepan. Stir in couscous and return to a simmer. Cover and remove from heat.
Oil the grill rack. Turn off one burner. Grill the chicken over direct heat until it is marked and releases easily, 4 to 5 minutes. Flip the chicken and baste with 1/3 cup of the reserved sauce. Grill until it releases easily, 4 to 5 minutes more. Move the chicken to indirect heat and cook until an instant-read thermometer inserted in the thickest part registers 165°F, 5 to 7 minutes more.
Fluff the couscous with a fork and stir in the remaining 1/3 cup sauce and pine nuts. Serve the chicken with the couscous and pickles.
Marinate chicken and refrigerate sauce (Steps 1-2) for up to 1 day. Refrigerate pickled peaches (Step 3) for up to 1 week.
4 metal or bamboo skewers