In bowl, whisk together oil, lemon rind and juice, garlic, dill weed, salt and pepper. Add chicken, turning to coat; let stand for 10 minutes. (Make-ahead: Cover and refrigerate for up to 4 hours.) Place chicken on greased grill over medium-high heat; close lid and grill, turning once, until no longer pink inside, about 12 minutes.
Top grilled chicken with lettuce and tomatoes, if desired.