Thaw turkey, if frozen. Remove skin and excess fat from turkey. In a small saucepan cook coriander, onion powder, chili powder, and red pepper in hot margarine for 1 minute. Remove from heat; stir in lemon juice. Brush over turkey. Insert a meat thermometer into the thickest part of turkey, not touching bone (if present).
In a grill with a cover arrange medium-hot coals around a drip pan. Test for medium heat above the pan. Place turkey on the grill rack over the drip pan. Cover and grill for 1-1/4 to 1-3/4 hours or until thermometer registers 170 degree F. Serve the turkey with Tomatillo Guacamole. Makes 8 servings.
In a small bowl stir together avocado, tomatillos, tomato, peppers, lemon juice, and garlic salt.