1. In medium bowl, combine zest and juice from lemon, olive oil, coriander, salt and pepper and stir to combine. Add chicken and toss to coat and let marinate, refrigerated, for ten minutes up to an hour. In small bowl, mix together mayonnaise and mustard together until combined and reserve.
2. Prepare grill for direct grilling over medium-high heat. Remove chicken from marinade, discarding any excess liquid, and place chicken on hot grill rack and cook 10 to 12 minutes or until chicken loses its pink color throughout and reaches an internal temperature of 165°, turning once.After turning chicken, place rolls, sliced in half horizontally for sandwiches, on grill rack and grill until lightly toasted until golden brown.
3. Remove chicken and rolls from grill and spread four bottom halves of rolls equally with prepared mayonnaise mixture. Top, in order, with lettuce leaves, grilled chicken, 2 slices bacon, avocado, and tomato followed by remaining top halves of rolls and serve warm.