Combine first 6 ingredients (sauce) in a bowl; stir well
Heat oil in a large skillet (wok) and stir-fry chicken until brown and done, about 5 - 10 minutes. Remove.
Add green onions, peppers and pineapple to the skillet; heat through
Pour in sauce and stir until thickened.
Return chicken to skillet, heat through.
Operating within the thermal limits of a residential cooktop requires managing moisture carefully when combining fresh fruit and lean poultry. High-heat stir-frying relies on rapid evaporation, which prevents ingredients from steaming in their own juices rather than browning. Cubing boneless chicken breast into uniform 1-inch pieces ensures even heat conduction during the initial five to ten minutes in the hot skillet. Combining soy sauce, white wine vinegar, mirin, grated ginger, garlic, and cornstarch creates a foundational marinade and thickening agent. Cornstarch gelatinizes between 203 degrees Fahrenheit and 212 degrees Fahrenheit, requiring a brief boil in the pan to achieve proper gloss and viscosity without floury raw starch flavors. Freezing this specific combination presents structural challenges because high-water-content vegetables like bell peppers and green onions lose their cellular integrity and turn limp upon thawing. Separating the cooked chicken and sauce base from fresh crisp-tender vegetables allows for successful meal prepping; freeze the protein and sauce mixture for up to two months, then combine with freshly chopped peppers and onions during the final reheat. Leftovers stored in an airtight container under 40 degrees Fahrenheit maintain safety for three days. Repurposing chilled second-day portions works effectively when folding the contents into warm cooked rice or wrapping them inside tight flour tortillas for a quick handheld lunch.