In a food processor or blender, process the onions and chiles to make a paste. In a small bowl, whisk together the dried plum purée, sugar, soy sauce, and tomato paste.
In a large nonstick skillet, heat the oil over high heat. Add the onion mixture and cook 1 to 2 minutes. Add the dried plum mixture, rice, and tofu; stir-fry until hot, about 5 minutes. Add the diced dried plums, peas, and scallions and stir-fry 2 minutes more. Transfer to a serving bowl or individual plates and garnish with peanuts, carrots, and cucumbers.