Place the grated cabbage and carrots in a bowl, sprinkle with a pinch of salt, and let rest for 5 minutes. Transfer to a clean kitchen cloth and squeeze firmly to extract as much liquid as possible.

Transfer the squeezed vegetables to a mixing bowl. Add all-purpose flour, cornstarch, minced ginger, minced garlic, black pepper, and salt. Mix well to form a cohesive mixture that holds together when squeezed.

Roll the mixture into small walnut-sized balls. Heat oil in a deep pan over medium heat. Drop the balls into the hot oil in batches and fry, turning occasionally, until golden brown and crisp, about 4 to 5 minutes. Remove with a slotted spoon and drain on paper towels.

Heat 1 tablespoon of oil in a separate pan or wok over high heat. Add minced garlic, minced ginger, green chilies, and the white parts of the spring onions. Stir-fry for about 30 seconds until aromatic.

Pour in the soy sauce, red chili sauce, tomato ketchup, and vinegar. Stir well, then pour in the water and bring the mixture to a simmer.

Stir the cornstarch slurry and pour it into the simmering sauce. Cook for 1 to 2 minutes until the sauce thickens and turns glossy. Add the fried vegetable balls, toss to coat evenly, garnish with spring onion greens, and serve hot.