Place 2 cups apple cider in a heavy saucepan and place over medium high heat. Bring to a boil then reduce heat to medium. Simmer at a low boil for about 10 minutes or till mixtures reduces by half. Remove pan from heat and add rice wine vinegar, mustard, lemon juice, honey, salt and fresh ground pepper.
Allow to cool for a few minutes then transfer to a bowl or other container and place in the refrigerator to cool completely. You can place it in the freezer to cool more quickly but check frequently and pull out as soon as it is chilled.
For the Salad
Finely slice the Napa cabbage and give it a rinse, draining well. Place the sliced cabbage in a large salad bowl. Transfer the contents of the bagged salad mix to your cutting board and run your knife through it a couple times. Add chopped mixed greens to the cabbage and toss to combine. Add the julienned carrots.
When the dressing has completely cooled, whisk in the olive oil. Core and thinly slice the apples, adding them to the dressing as you work, to prevent them from discoloring. Use a spoon to transfer the apples from the dressing to the salad and then toss the salad with just enough dressing to lightly coat the ingredients.
Top the tossed salad with the chopped fresh chives, walnuts, and crumbled Gorgonzola cheese.
Prep time shown does not include time to chill dressing.