Heat 1 tbsp olive oil in a large pan. Add in the ground beef and break it apart with a cooking spoon into smaller pieces. Season with salt and pepper to taste and cook till no longer pink. Set aside on a separate plate.
In the same pan, cook the onion, garlic, and ginger for 3-4 minutes. Add the meat and water chestnuts into the pan.
Stir in the hoisin sauce and soy sauce and cook everything together for a few minutes.
To serve, place the meat mixture in the lettuce cups and top with shredded carrots, peanuts, sesame seeds, green onion, and extra hoisin sauce.