Make the pineapple cooking sauce by mixing together the pineapple juice, water, ketchup, rice vinegar, soy sauce and sugar. Set aside.

Prepare the tofu for frying by either pressing it first for 20 minutes and then cutting it into cubes or you can use pre-pressed tofu.

Add the cubes of tofu to a large bowl and toss with the garlic powder, onion powder, salt, pepper and 2 Tbsp of cornstarch. Set aside while your oil comes to temperature.

Heat the oil in a smallish pot with high walls. Bring the temperature to about 350 degrees.

Spread out the remaining 3 Tbsp of Cornstarch onto a plate. Lightly coat all sides of the tofu in the cornstarch before placing into the hot oil.

In a large skillet on medium heat sauté the garlic and ginger in sesame oil until both become fragrant, about 2-3 minutes. Add in the red bell pepper, red onion, green onions and cook until they become slightly tender. Remove from pan.

In the same pan add the pineapple sauce and turn the heat to medium-high. Bring to a boil and let the sauce reduce just a bit before adding in the cornstarch slurry. Mix well until the sauce begins to thicken.

Add the cooked vegetables, tofu and pineapple chunks. Mix well until everything is well coated with the sauce. Season with salt & pepper and cook until heated through.

Garnish with reserved green onions and serve over rice or noodles.