Rinse preserved lemon; remove pulp, and discard. Cut rind into 1/4-inch cubes.
Whisk together lemon juice and next 5 ingredients in a large bowl; add lemon rind, tomato, and next 5 ingredients, tossing to coat. Cover and chill 30 minutes. Serve over salad greens.
Lively Lemon-Chicken Salad: Double the lemon juice mixture, reserving half for tomato mixture. Place 4 skinned and boned chicken breast halves in a shallow dish or large heavy-duty zip-top plastic bag; pour remaining half of lemon juice mixture over chicken. Cover or seal, and chill 20 minutes. Remove chciken from marinade, discarding marinade.
Cook chicken in a large nonstick skillet over medium-high heat 6 to 7 minutes on each side or until done. Serve with tomato mixture over lettuce.