Combine water and salt in a saucepan and bring to a boil. Add rice and carrots. Cook until rice is tender yet firm to the bite, about 8 minutes. Drain and rinse; set aside to cool. Drizzle tamari and rice vinegar over cooled rice and stir.

Preheat the oven to 400 degrees F (200 degrees C). Line a large baking sheet with parchment paper.

Combine cooked rice mixture, ground pork, peas, green onion, egg, ginger, garlic powder, salt, and white pepper in a large bowl. Mix by hand until just combined; do not overmix. Shape mixture into 25 to 30 golfball-sized meatballs and place on the prepared baking sheet.

Bake in the preheated oven until browned on the outside and no longer pink inside, about 22 minutes.

While meatballs are cooking, combine cornstarch and water in a bowl and whisk well.

Combine pineapple juice, sugar, white vinegar, and rice vinegar in a saucepan and bring to a boil, stirring constantly. Add 1 tablespoon of the mixture to the cornstarch mixture and stir well. Pour cornstarch mixture into the saucepan, whisking constantly. Reduce heat to medium and whisk until thickened, 3 to 4 minutes. Remove from heat and pour sauce into a deep serving dish.

Arrange baked meatballs on a serving plate. Sprinkle with parsley and serve hot with sauce on the side or drizzled over meatballs.