Boston bibb or butter lettuce leaves, washed and dried
In a large pan over medium heat, cook the ground beef and break into tiny pieces with a spatula. When almost no pink remains (it'll finish cooking later), remove the beef to a plate or bowl and set aside.
Drain most of the grease out of the pan, reserving about a teaspoon. Add the onions and cook until softened, and then add the garlic and cook for 1 minute more. Add the hoisin sauce, soy sauce, vinegar, ginger, and chili paste. Stir to combine.
Heat for a few minutes and then return the beef to the skillet. Add the green onions and continue cooking until green onions begin to soften and beef is fully cooked. Stir in the sesame oil and serve on lettuce leaves topped with chopped peanuts