To make the egg roll, heat 2 tablespoons of the olive oil in a large skillet or wok over medium heat. Add the ginger and garlic and cook, stirring until slightly softened, about 2 minutes. Add the pork and stir until it turns white, about 2 minutes. Transfer the pork to a plate and set aside. Add the scallions, carrot, and red pepper to the skillet. Cook, stirring, until slightly softened, about 2 minutes. Add the cabbage, stock, and soy sauce. Reduce the heat to medium-low and simmer until the liquid has evaporated and the vegetables are tender, about 5 minutes. Return the pork to the skillet and let the contents of the skillet cool to room temperature. You should have about 2 cups.
Lay the wrappers flat on a work surface. Brush the edges lightly with water. Top with about 1 tablespoon of the filling and roll into a cylinder, tucking in the sides and pressing the edges to seal. (The egg rolls can be frozen at this point.) Heat the remaining olive oil in a large nonstick skillet over medium-high heat until almost smoking. Working in batches, add the rolls and cook, turning often with tongs, until golden brown on all sides, 5 to 7 minutes. Cool slightly before serving.
To make the dipping sauce, combine the soy sauce, vinegar, sesame oil, and sugar in a small bowl. Stir well and serve on the side with the rolls.
Yield: 1/2 cup