Cut the backbone of the chicken and cut small slits on the chicken breasts, legs and thighs.
Combine ingredients for marinade in a bowl. Mix well until it forms a paste. Rub all over chicken. Cover and chill to for at least 3 hours.
Basting sauce: Combine olive oil, chilies and garlic in a small saucepot. Cook over low heat for about 5 minutes. Set aside.
For the Piri Piri sauce, heat olive oil in saucepan. Sauté garlic then add chilies, oregano, paprika powder and red wine vinegar. Season with salt and pepper. Simmer for 3-5 minutes. Let cool then transfer into a blender. Puree until smooth. Set aside.
Grill chicken while continually basting with sauce until cooked. Optional: Finish chicken by baking in the oven at 180°C. Serve chicken with Piri Piri sauce on the side.