In the container of a food processor or blender, place 1 tb of the olive oil, 1 tb of the vinegar, quarter tea each mustard, salt and pepper; process 15 seconds. While processor is running, add 2 more tb olive oil and process 10 seconds. Add remaining 3 tb vinegar, remaining 3 tb olive oil, garlic, and lemon peel. Finally add chives and process about 15 seconds more.

Dip each piece of chicken in sauce and coat well. Marinate in refrigerator at least 4 hours (or overnight).

Place chicken on prepared grill, skin side up, about 20 cm from heat. Sprinkle with remaining 0.75 ts salt and quarter ts pepper. Grill, turning and basting with sauce every 10 minutes, about 1 hour or until fork can be inserted into chicken with ease.