Heat a small saucepan over medium-high heat.
Add oil and onion and sauté for 2 minutes or until tender.
Stir in tomato puree, remaining ingredients and 1/4 teaspoon salt.
Reduce heat to low, and cook 5 minutes, stirring occasionally.
Skewer chicken pieces, 2 half thighs per skewer.
Coat chicken in olive oil, season and cook on a hot grill pan for 6 minutes on each side or until done.
Baste chicken generously with sauce, turn over, and grill for 2 minutes. Baste again, turn over and grill for 2 more minutes.