3/4 to 1 pound fajita beef (sirloin flap or skirt steak), cut diagonally across the grain into ¼-inch strips
1 cup peanut or canola oil
3 tablespoons chili flakes (or ground chilies)
1 teaspoon ground roasted Sichuan pepper
1/2 yellow or red onion, cut in thin strips
1/2 red bell pepper, cut in thin strips
4 to 5 green chili peppers (jalapeño or serrano), cut in thin strips (seeded only if you must)
1 tablespoon Shaoxing wine
1 teaspoon sugar
1 teaspoon salt
1/4 cup cilantro, cut in sections
4 teaspoons chili oil
2 teaspoons Sichuan pepper oil
2 teaspoons sesame oil
Heat wok until hot. Add enough oil to deep-fry the meat, about 1 cup. Heat oil just until a test piece sizzles (300° F or 150°C; it should not be hot enough to brown the meat). Fry beef strips until they are just cooked through, then remove and let drain on paper towels.
Turn on the exhaust fan or open doors in preparation for chilies!
Clean the wok, return it to the heat until hot, then add 3 tablespoons fresh oil. Heat the oil briefly, then add chili flakes and Sichuan pepper and cook until fragrant, but do not burn. Add back the beef and stir-fry until it is starting to brown.
Add the onions, red bell pepper and green chili peppers and stir-fry until peppers are just beginning to wilt.
Add the Shaoxing wine, sugar and salt, constantly tossing and turning the meat. Then add the cilantro, chili oil, Sichuan pepper oil and sesame oil to finish the dish, stir-frying briefly to meld flavors. Garnish with fresh cilantro sprigs.