Combine the soy sauce, black vinegar, garlic, ginger, 1/4 cup of the rice flour, 1/4 cup of the cornstarch, and the five-spice powder in a one-gallon zip-top bag. Seal the bag and squish (yes, that's a technical term), the ingredients to combine. Add the pork to the bag, the re-seal, repeating the squish to coat the pieces. Refrigerate for 6-8 hours.
Move the pork to a colander or other strainer and leave for 5 minutes to thoroughly drain. Discard the marinade.
Add 3 cups of oil to an 11-inch high-sided skillet. (It should measure 1/2 inch deep.) Attach a candy/fry thermometer to the pan and bring the oil to 350 F over medium-high heat, adjusting the heat as needed to maintain the temp.
Combine the remaining rice flour and cornstarch in a shallow bowl or pie pan. Add half of the pork and toss with your hands to thoroughly coat each piece. Transfer the meat to a sheet pan fitted with a wire rack and repeat with the second half of the pork. Rest for 10 minutes to help set the outer coating.
Carefully place half of the dredged pork into the oil and stir to fully submerge. Fry, stirring occasionally, until browned and crispy, about 3 minutes. Transfer to a paper towel lined plate or sheet pan. Let the oil come back to temp and repeat the process with the second batch of pork.
Once all the pork has been browned, kill the heat and leave the skillet to cool for a few minutes. Meanwhile, whisk the ketchup, sugar, rice wine vinegar, and honey together in a medium bowl and set aside.
Carefully drain all but 1 tablespoon of the fry oil from the skillet. (The oil will still be hot, so be sure to use a heatproof bowl or measuring cup.) Place the skillet back over medium heat for 1 minute then add the onion and carrot and cook for 3 minutes, stirring occasionally. Add the bell peppers and snap peas and cook another 2 minutes.
Return the pork to the skillet along with the pineapple and the sweet/sour sauce, and stir to evenly coat. When the sauce begins to bubble, reduce the heat to medium-low and simmer until slightly thickened, stirring frequently, 4-5 minutes.
Serve immediately over the rice, or if you prefer, wide egg noodles.