Step 1Heat the oven to 300 degrees. Spread the macadamias in a metal cake pan and toast 10 minutes. Cool, then chop into coarse chunks.
Step 2Combine the mustard, one-half teaspoon sea salt and several grinds of pepper in a small bowl. Whisk in the lemon juice, then the macadamia oil. Add the chives and whisk until emulsified. Taste and adjust the seasoning.
Step 3Toss the arugula with just enough dressing to coat lightly. (Reserve any remaining dressing for another use.) Arrange on 4 salad plates. Cut the pears into thin slices and divide among the plates. Sprinkle with the cheese and then with the macadamias and serve at once.