In a small saucepan, combine the soy sauce, honey, rice vinegar, water, sesame oil, ginger, and garlic. Bring to a simmer over medium heat.
- Mix the cornstarch with water in a small bowl, then add it to the sauce. Stir well and let it simmer for 2-3 minutes until it thickens. Remove from heat and set aside.
- Preheat the air fryer to 375°F (190°C). Toss the cauliflower florets with olive oil, salt, pepper, and garlic powder (if using) in a large bowl.
- Place the cauliflower in the air fryer basket in a single layer. Air fry for 15-18 minutes, shaking halfway through, until golden and crispy.
- Transfer the cauliflower to a serving bowl and drizzle with the prepared teriyaki sauce. Toss to coat evenly.
- Garnish with sesame seeds, green onions, or fresh cilantro if desired. Serve immediately.