Using a vegetable peeler, peel twelve 1⁄2” wide strips of zest from the top to the bottom of 2 of the lemons and set aside. (If using a mixture of oranges and lemons, peel zest from the orange.) Juice all 3 lemons (or the orange and lemon) into a measuring cup; you should have 1⁄2 C.

In a large bowl, combine 1⁄4 C. of the juice, the 2 Tbsp. olive oil, 1 tsp. of the garlic, the oregano, and bay leaves. Add the chicken, lemon strips, and onions and toss to coat evenly. Cover and refrigerate for at least 2 hours or up to 4 hours.

Soak twelve 8-inch bamboo skewers in water for 20 minutes.

In a food processor, combine the remaining 1⁄4 C. juice, remaining 1 tsp. garlic, the green onions, basil, cilantro, parsley, tarragon, orange zest, cayenne, allspice, cumin, and cinnamon. Process until smooth. With the machine running, gradually add the remaining 1⁄2 C. olive oil in a slow, steady stream until thoroughly incorporated.

Preheat a gas grill to medium-high. Thread the chicken on the skewers, alternating with the lemon strips, bay leaves, and onion pieces. Brush lightly with olive oil. Sprinkle with salt and pepper. Place in the center of the grill, cover, and cook, turning once or twice, until opaque throughout, 5-8 minutes. Divide among 6 small plates. Serve the sauce in small bowls alongside.