Heat a skillet to medium-high heat with the beef. Cook for 5 - 7 minutes, breaking the meat up as it cooks until crumbly and browned. When the meat is mostly cooked, add the hoisin, oyster sauce, and sriracha. Stir to combine, and add the water to form a sauce. Taste the meat, and add soy sauce 1 teaspoon at a time to your taste. Add some more sriracha too, if you'd like. Reduce the heat to medium-low, and let the meat simmer for 5-10 minutes until the water is partially reduced and the meat is cooked through.

Meanwhile, broil the buns on the cut side until lightly toasted.

To serve, pile some lettuce on the bun bottoms. Top with some of the meat mixture, sliced green onions, and cilantro leaves. Add extra sriracha over the meat if you'd like. Top with a bun top, and enjoy!