Trim 1 pound Brussels sprouts of any ragged or browning ends, peeling off any leaves that look dried out or are just not looking great. Cut the sprouts in half lengthwise (unless they're very small, in which case you can leave them whole, or are very large, in which case quarter them).
Add the sprouts to a medium bowl and toss them with 2 Tablespoons canola oil, 1 ½ teaspoons curry powder, and ½ teaspoon kosher salt.
Spread the seasoned sprouts into a single layer on a large air fryer tray (or two if your air fryer is on the smaller side). Heat the air fryer to 375°F and cook the sprouts for 10 minutes, shaking or stirring the sprouts around once during cooking. The sprouts should be paler/brighter green and just starting to brown. Increase the temperature of the air fryer to 450°F and cook for an additional 5 minutes, shaking and/or stirring the sprouts once during cooking. The sprouts should now be well-browned and cooked through.
While the Brussels sprouts are cooking, pulse 2 Tablespoons sesame seeds and a pinch (or up to ⅛ teaspoon) of additional kosher salt together in a clean spice grinder until they form a powder (don't over-grind or you run the risk of making sesame paste). Set aside.
Transfer the sprouts to a serving dish and sprinkle evenly with the sesame powder. Serve immediately with a sprinkle of lemon juice.