1. To prepare chicken, combine the first 5 ingredients in a large zip-top plastic bag. Add the chicken to the bag; seal. Marinate in refrigerator 1 hour, turning the bag occasionally.
2. Prepare grill.
3. Remove chicken from bag; discard marinade. Place chicken on grill rack coated with cooking spray; grill 5 minutes on each side or until chicken is done. Let chicken stand 10 minutes; cut across grain into 1-inch-thick slices.
4. To prepare dressing, combine cilantro and next 7 ingredients (through 1/4 teaspoon cumin) in a small bowl, stirring well with a whisk.
5. To prepare salad, arrange 2 cups greens, 1/4 cup cucumber, 1 tablespoon onion, and 2 tomato wedges on each of 4 plates; top each serving with 1 chicken breast half. Drizzle 2 tablespoons dressing over each serving.