In a bowl, combine the pineapple juice, ketchup, brown sugar, vinegar, water, soy sauce, pepper flakes, and sesame oil. In a medium saucepan, heat 1 tablespoon of the oil over medium-high heat. Add the ginger and garlic, and cook, stirring, for 15 seconds. Add the pineapple juice mixture and bring to a boil. Reduce the heat and simmer, stirring, until the sugar dissolves, 2 to 3 minutes.
In a bowl, dissolve the cornstarch in the sherry. Add to the simmering sauce and whisking constantly. Reduce the heat and simmer until thickened, 2 to 3 minutes. Remove from the heat.
Season the pork with the Essence. In a wok or large saute pan, heat 1 tablespoon of the oil over high heat, swirling to coat the sides. Add the pork and cook, stirring, until golden brown, 2 to 3 minutes. Remove and drain on paper towels.
Return the wok to high heat. Add the remaining tablespoon of oil, swirling to coat the sides. Add the bell peppers and onions, and cook, stirring, until wilted, 1 to 2 minutes. Reduce the heat to medium-high. Add the sauce and bring to a boil until thickened. Add the pineapple and pork, and cook, stirring, until warmed through, 1 minute. Remove from the heat and adjust the seasoning to taste. Divide the rice among 4 dinner plates, and top with the pork and sauce. Garnish each with the nuts and green onions, and serve immediately.
Yield: 4 servings