How to Make It
In a small bowl, cover the dried shrimp and scallops with the boiling water and let stand until softened, about 15 minutes. Drain well.
In a mini food processor, combine the shrimp, scallops and ham with the garlic, shallot, ginger, soy sauce, crushed red pepper and sugar. Pulse until minced. Scrape the mixture into a small saucepan and stir in 1 cup of the oil. Bring to a boil over moderately high heat; reduce the heat to a simmer and cook until the solids are dark golden and fragrant, about 30 minutes. Remove the XO sauce from the heat and let cool to room temperature.
Heat a large wok or skillet over high heat for 5 minutes. Drizzle in the remaining 1/4 cup of oil, add the green beans and cook for 2 to 3 minutes, tossing every 30 seconds; the beans are done when they’re tender and blistered in spots. Drain off the oil. Stir in 1/4 cup of the XO sauce; toss until the beans are evenly coated. Season with salt and pepper and transfer to a platter. Serve with lemon wedges.
Dried shrimp and dried scallops are both available at Asian markets.