Prepare grill for direct-heat cooking with medium-hot charcoal; see “Grilling Procedure,” page 168.
Coarsely grind chiles, spice seeds, garlic, and peppercorns in grinder or with mortar and pestle, then stir together with salt and oil in a bowl to form a spice paste. Rub paste all over chicken.
Oil grill rack, then grill chicken, skin sides down first, over coals, turning over occasionally and moving around if flare-ups occur, until browned, 4 to 5 minutes total. 3Move chicken to area with no coals underneath, arranging chicken so that thicker sides are closest to coals, then cover with inverted roasting pan and grill, turning chicken over once, until just cooked through, 15 to 17 minutes. Transfer to a platter
and let stand 5 minutes before serving.
Cooks’ notes: Chicken can be grilled on a gas grill. Preheat all burners on high, covered, 10 minutes. Reduce heat to moderately high and brown chicken, skin sides down first, covered, turning over occasionally, about 4 minutes. Turn off 1 burner (middle one if there are 3) and put chicken, skin sides up, above shut-off burner, then grill, covered, without turning, until just cooked through, 15 to 20 minutes.
• Chicken, rubbed with spice paste, can marinate, covered and chilled, up to 4 hours before grilling.
• Spice paste keeps, covered and chilled, up to 1 week.
SPECIAL EQUIPMENT: An electric coffee/spice grinder or a mortar and pestle; a 17- by 12- by 3-inch disposable aluminum roasting pan (if using charcoal)