Rinse chicken and pat dry. Cut into 1-inch pieces; place in large bowl. Sprinkle with 1/2 teaspoon salt and lemon juice. Marinate, covered, for 30 minutes. Combine tomato puree, garlic, ginger root, coriander, allspice, nutmeg, turmeric, chili powder, 1/2 teaspoon salt, yogurt and oil in food processor container. Process until smooth. Mix with chicken. Marinate, covered in refrigerator for 6 to 8 hours. Remove chicken from marinade, reserving marinade. Thread chicken pieces 1/4 inch apart onto skewers. Place in foil-lined baking pan. Coat with part of the reserved marinade. Bake in center section of oven at 450 degrees for 6 to 8 minutes. Turn skewers. Coat with remaining marinade. Bake for 6 to 8 minutes or until chicken is cooked through. Serve on or off skewers.