Step 1: Cut the chicken into 1-inch cubes. Cut the onion in half widthwise. Cut each half in quarters and break each quarter into individual segments. Thread the chicken cubes onto bamboo skewers alternating with pieces of onion. Arrange the kebabs in a baking dish or foil pan just large enough to hold them. Season on all sides with salt and pepper.
Step 2: Make the Charmoula: Combine the parsley, cilantro, and garlic in a food processor and finely chop. Add the salt, spices, lemon juice, oil, and water and process to a coarse purée, running the machine in short bursts. Correct the seasoning, adding salt and/or lemon juice; the charmoula should be highly seasoned. Spoon half the charmoula over the chicken kebabs, turning the kebabs so they marinate evenly. Let marinate in the refrigerator while you make the sauce and light the fire.
Step 3: Make the sauce: Cut the tomatoes in half widthwise and wring out the seeds. Grate each tomato on the coarse side of a box grater into a mixing bowl. The idea is to grate the tomato flesh. Discard the skin. Stir the remaining charmoula into the grated tomatoes. Taste for seasoning, adding salt or lemon juices to taste.
Step 4: Set up your grill for direct grilling and preheat to medium-high. Brush and oil the grill grate.
Step 5: Drain the chicken kebabs and arrange on the grate. Grill until browned on the outside and cooked through, about 3 minutes per side. Serve the chicken kebabs with the charmoula tomato sauce for spooning over them, and Moroccan bread or grilled pita on the side.
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Steven Raichlen’s Project Smoke is a production of Maryland Public Television, Barbacoa, Inc., and Resolution Pictures. © 2017 Barbacoa, Inc.