Preheat the air fryer to 375°F for 5 minutes. Lightly spray the inside of the hot air fryer basket with non aerosol cooking spray.

Pat the sliced skirt steak very dry with paper towels. Arrange the steak in a loose, even layer in the basket, leaving space between pieces so they do not overlap.

Air fry the steak at 375°F for 5 to 7 minutes, shaking the basket halfway through, until the strips are browned at the edges and just cooked through. Transfer the hot beef to a large bowl and set aside. Return the empty basket to the air fryer to keep it warm.

In a medium bowl, combine the broccoli florets with the canola oil and toss until evenly coated.

Add the oiled broccoli to the air fryer basket in a single layer. Air fry at 375°F for 6 to 8 minutes, shaking once or twice, until the tips are lightly charred and the stems are crisp tender. Transfer the hot broccoli to the bowl with the steak.

While the broccoli cooks, whisk together the water, soy sauce, brown sugar, rice vinegar, garlic, ginger, sesame oil, red pepper flakes, and cornstarch in a microwave safe bowl until smooth.

Microwave the sauce on high for 1 minute, then whisk well. Continue microwaving for 30 to 60 seconds more, whisking once, until the sauce is thick, glossy, and pourable.

Pour the hot sauce over the warm beef and broccoli. Gently toss until everything is evenly coated.

Sprinkle with sesame seeds and serve immediately.