Cut potatoes into small, even pieces. Spray with avocado oil cooking spray, season with salt and pepper and air fry at 385°F for 15-18 minutes, until crispy. Set aside to let cool slightly.
While potatoes cool, chop onion and dill, and wash arugula. Combine in a large bowl, add crumbled feta, and set aside while you make your dressing.
Combine all dressing ingredients in a mason jar and shake well to combine.
Add cooled crispy potatoes to the arugula salad and toss with dressing right before serving. If not serving immediately, store salad and dressing separately to prevent the salad from getting soggy.
If desired, add your choice of protein (salmon or chicken are both great here) to make this a complete meal!