Heat a large skillet over medium-high heat. Add the beef and cook, breaking it up with a spoon, until browned, 5 to 7 minutes.
Stir in the hoisin, 2 tablespoons of the soy sauce, and the Sriracha.
In a small bowl, combine the vinegar, oil, the remaining teaspoon of soy sauce, and ¼ teaspoon each salt and pepper.
Divide the lettuce, cucumbers, mango, cooked beef, cilantro, and peanuts among bowls. Drizzle with the dressing.