Make chicken marinade. Combine water, salt, garlic powder, and liquid smoke in a medium bowl. Mix to dissolve salt. Place chicken in marinade, cover, and refrigerate for 3 hours.
Make balsamic vinaigrette. Whisk together all ingredients except oil in a medium bowl. Gradually pour oil in while whisking continuously. Cover and refrigerate.
Make candied walnuts. Combine (in order listed) the peanut oil, honey, sugar, vanilla, and salt in a medium skillet over medium heat. When mixture starts to bubble, add walnuts and stir constantly until sugar begins to caramelize. Turn off heat and keep stirring walnuts so they do not burn. After 1 minute of stirring. Pour nuts onto a piece of wax paper to cool.
Grill chicken. Heat a gas grill or grill pan over medium-high heat. Remove chicken from marinade and blot dry with paper towels. Rub with oil and season with pepper. Grill for 3 to 4 minutes per side, or until done. Let cool and slice.
For each salad, toss together 2 cups romaine, 2 cups red leaf lettuce, half of the apple, onion, celery, and blue cheese. Mix in desired amount of dressing and top with sliced chicken and walnuts.