Heat oil in a large skillet or wok over medium-high heat. Dredge prawns in flour, then fry in the hot oil until golden. Remove to paper towels to drain.
In a medium bowl, whisk together the chile sauce, pomegranate juice, Sriracha hot sauce, hot ketchup, regular ketchup, soy sauce, lemon juice and lemon zest. Pour the sauce into a wok, and bring to a boil over medium-high heat. Cook until the sauce has reduced by about 10 percent and has thickened slightly. Mix the prawns into the sauce, and toss to coat. Serve immediately.
