Dain the tofu, then wrap in a paper towel to remove excess water. Cut into cubes, then toss with 1 tablespoon of cornstarch and set aside. Air fry on 400 for 10 minutes.
In a small bowl, whisk together the remaining tablespoon of cornstarch and water until combined. Then, whisk together the remaining sauce ingredients: ½ cup ketchup, 3 tablespoons pineapple juice, 3 tablespoons rice vinegar, ¼ cup sugar, 1 tablespoon Worcestershire sauce and ½ teaspoon red chili flakes
Heat oil in a large skillet or wok over medium heat. Add the onions, garlic, and peppers to the skillet and cook until veggies are softened and caramelized, for about 5 minutes, tossing often. Add the pineapple and the sauce and cook until the sauce thickens, about 2 minutes. Add the tofu back in and coat until warmed through with the sauce.
Remove from heat and add in the scallions. Serve over warm rice.
