Add ground turkey and onions to a large sauté pan over medium heat.
Brown meat and cook onions until all the pink in the meat is gone; stirring frequently, 5 minutes.
Add cumin, cayenne (if using), salt and pepper, stir to combine, and continue to cook for an additional 1-2 minutes. Turn off heat.
Meanwhile, in a small bowl, whisk together tamari, mustard, and hot sauce.
Pour sauce over the browned meat. Add the carrots and cilantro, stir.
Remove root ball from lettuce and wash leaves. Pat dry with paper towels.
Spoon meat mixture onto the lettuce leaves and enjoy!