Mix all sauce ingredients, except for arrowroot starch and water, in a small bowl and set aside.
Heat a large skillet on the stove, add oil, and then ground beef. Break the beef into small chunks and let cook.
When the beef is mostly cooked, but not all the way, add salt and mix to combine.
Next, add the onion and pineapple to the ground beef and cook until soft.
Next, add the minced garlic and ginger to the pan and stir and cook for a minute or two, or until the garlic and ginger become fragrant.
While the filling is cooking, pour the sauce mixture into a small saucepan and heat over medium-high heat.
Let the sauce come to a light boil, then simmer for about 2 minutes. Then turn the heat off on the stove.
Mix the arrowroot starch and water in a small bowl and then pour into the sauce.
Stir for a minute or two, or until the sauce thickens.
Serve the meat and pineapple filling in individual lettuce leaves and top with the sauce, shredded carrots, cilantro, and extra lime. Enjoy!