Finely grate peel from 1 lemon into a blender. Squeeze in ¾ cup juice. Add cilantro, oil, garlic, chilies, coriander seeds, paprika, sugar, turmeric and salt. Purée just until blended. Measure out ½ cup; cover and refrigerate for use later.
Place chickens in a large casserole dish. Pour remaining marinade overtop. Rub all over chickens and under the skins. Cover and refrigerate for at least 4 hours, preferably overnight.
Before grilling, let stand at room temperature for 30 minutes. For gas grills, preheat to medium high. After 10 min, turn off the middle burner. If using charcoal, bank coals on one side of grill.
Place chickens, skin side up, on indirect side of grill. Close lid and grill, rotating so that it cooks evenly, for 20 minutes. Occasionally baste with sauce.
Turn chickens over; generously baste with sauce. Cover and continue to barbecue, rotating often until skin is deep golden and crisp and a thermometer inserted into thickest part of thigh reads 180°F, about 20 to 25 more minutes. Add limes, cut side down, for last 5 minutes.
Remove to a cutting board and let rest for 10 minutes. Cut each chicken into 4 or 5 pieces and drizzle with reserved marinade.
Nutrients per serving: 658 calories, 55 g protein, 45 g fat (10 g saturated fat), 7 g carbo-hydrates (1 g fibre), 175 mg cholesterol, 425 mg sodium.
Best Health tip: Be sure to allow time for the chicken to marinate – the longer, the better. I recommend four hours.