Combine olive oil, lemon juice, red wine vinegar, oregano, thyme, garlic, lemon rind, salt and pepper in a large bowl. Add chicken and toss until well coated with marinade. Let stand for 10 to 30 min.Heat barbecue or oiled grill pan on high heat.Thread chicken on skewers (if you are using wooden ones, you will need to soak them for 30 min in advance). Grill pork for 10 min, turning occasionally, or until browned at the edges and cooked through but still juicy.Combine yogurt, garlic and salt in a bowl and stir together.Serve chicken with yogurt sauce. You can also include cucumber and tomato slices with a simple vinaigrette as a side.