Preheat the air fryer to 360ºF while you prepare the cauliflower, so it's ready to use right away.
Cut the cauliflower into evenly-sized pieces, making sure to cut the thick stems in half so that they will cook faster. In a large bowl, toss the cauliflower with the olive oil and salt, and use your hands to make sure the oil is evenly distributed.
Pour the cauliflower into the air fryer basket or tray, arranging it into roughly a single layer. (If you want to work with more than 1 pound of cauliflower at a time, you'll probably have to work in batches to get crispy results.)
Set the air fryer to cook for 10 minutes at 360ºF. When the timer goes off, shake the basket to make sure the cauliflower is turned during the cooking process.
Return the cauliflower to cook for 10 more minutes. (So, you're cooking the cauliflower for 20 minutes total.)
Serve the cauliflower warm right away, with a squeeze of fresh lemon juice to brighten up the flavor. (It's so good!) Sprinkle with freshly chopped parsley, if desired.
If you're using a multipurpose convection oven (like the Cuisinart air fryer) I've found that it tends to run hot. You may want to lower the temperature to 325ºF in this case, to get similar results to the deeper basket-style air fryers. I also keep my shelf on the lowest rack in my convection air fryer, so that the top of the vegetables won't burn too quickly.