Start by preparing the sauce. Whisk together all the sauce ingredients and set aside. Next, add the oil to a large pan over medium heat. Once the pan is hot, add the meat and cooked until cooked through, about 4 minutes or so. Add the garlic, green onions and peanuts, stirring 3-4 minutes or so. Pour in 3/4 of the sauce and mix to coat well. Let cook for a few minutes, then remove from the heat. Add the lime juice and mix again. Fill up the lettuce cups with mixture, drizzle remaining sauce on top, add chopped cilantro and enjoy.