Chicken Anticuchos

Look for aji amarillo pasta, a spicy Peruvian condiment made with yellow chili peppers, in Latin American markets. It goes well with marinades and meat rolls.
Combine 1/4 cup vinegar, aji amarillo paste, 2 teaspoons cumin, black pepper, salt, and garlic in a mini food processor; beat until smooth. Pour the marinade into a large zippered plastic bag.Cut the chicken into 2-inch-thick cubes. Place the chicken cubes in the marinade bag; mix well to coat. Marinate in the refrigerator for at least 45 minutes or a maximum of overnight.Peel the onion; cut into 1-inch-thick slices. For bell peppers, remove the stem, seeds, and membrane; cut into 1-inch-thick pieces.Remove chicken from marinade; drain marinade. Line the chicken and veggies evenly on 8-inch skewers, alternating between the chicken and veggies.Combine the remaining vinegar, remaining cumin, oil, a pinch of salt, and a pinch of pepper in a small bowl.Preheat the grill to medium-high heat. Place the skewers on a grill rack greased with cooking spray; cook the skewers for 2 minutes on each side or until the chicken is tender, drizzling frequently with the vinegar mixture.