Step 1

Place tofu between 2 plates. Place a weight on the top plate to press water out of tofu. Let sit, draining off water occasionally, 1 to 2 hours.

Step 2

Slice tofu into chunky, bite-sized pieces.

Step 3

Heat oil in a large skillet over medium-high heat. Saute tofu until golden, about 5 minutes. Remove tofu and set aside.

Step 4

Whisk pineapple juice, brown sugar, vinegar, cornstarch, tamari, and salt together in the same pan. Stir constantly over medium heat until thickened, 3 to 5 minutes. Add pineapple chunks, bell peppers, and onion; reduce heat to low. Cook until onion and peppers are slightly soft, about 5 minutes. Add tofu and heat through, 2 to 3 minutes more. Serve over cooked rice.