Put the tofu cubes in a bowl, add soy sauce, and pineapple juice. Toss well. Spread on a baking sheet and bake in a pre-heated oven for around 15 minutes at 200° C.
In a bowl mix soy sauce, pineapple juice, tomato ketchup, vinegar, sriracha, and water. Keep aside.
Heat oil in a pan. Add ginger, garlic, and chopped chilies. Saute for around a minute and then add spring onion white. Saute for another minute.
Add bell pepper and stir fry for 2-3 minutes.
Add the sauce mixture, water, and simmer for 2-3 minutes
In a bowl mix corn starch with around 2 tablespoons of water and add to the pan. Mix well and cook for 1-2 minutes or till the sauce thickens.
Finally, add baked tofu, pineapple chunks, and spring onion greens. Mix and switch off the gas.
Serve with steamed jasmine or sticky rice.