Preheat the air fryer to 400ºF and coat the air fryer basket with 1 teaspoon of avocado oil.
Add the red onion to a bowl and toss with vinegar and ¼ teaspoon of salt. Set aside for later.
In a large bowl, toss the Brussels sprouts with 2 tablespoons of avocado oil and ½ teaspoon of salt. Transfer the brussels sprouts to the air fryer basket. Depending on the size of the air fryer, you may need to cook the brussels sprouts in two batches. We have an XL air fryer, so we were able to add all of the brussels sprouts (about 2 layers). Smaller air fryers may need two batches to get the brussels sprouts crispy.
Cook for 7 minutes and then toss. Continue cooking for 5-7 minutes or until the brussels sprouts are brown and crispy. Remove from the air fryer to rest.
Line the air fryer with a silicone liner or a tin foil bowl. Add the almonds and toss them with maple syrup, poppy seeds, and flakey sea salt until coated.
Cook the almonds for 5-7 minutes, tossing every few minutes. The almonds should be golden brown.* Remove the almonds from the air fryer.
Add the brussels sprouts, golden raisins, red onions (plus vinegar), and almonds to a bowl and toss.
Add all of the ingredients for the dressing to a mason jar. Shake the ingredients together until combined.
Pour half of the dressing over the salad and toss. Adjust the amount of dressing based on your desired taste.
Top with parmesan cheese and enjoy.