Place a baking rack on a sheet pan and lay the bacon slices on the rack. Roast the bacon for about 20 minutes, until nicely browned. Allow to cool.
In a large bowl, toss together the arugula, apple, walnuts, cranberries, and blue cheese. For the dressing, whisk together the vinegar, orange zest, orange juice, mustard, maple syrup, 1 1/2 teaspoons salt, and the pepper in a bowl. Slowly whisk in the olive oil.
Chop the bacon into large pieces and add it to the salad. Toss the salad with just enough dressing to moisten. Sprinkle with 1/2 teaspoon salt and toss well. Serve immediately.