In a small sauce pan, sweat the onion and jalapeno if using. Add the garlic and cook another twenty seconds. Add beans, cumin and half of the lime juice and stir. Add the water and blend with an immersion blender or in a blender until smooth. Season to taste and keep warm. Grill your Kansas City Strip Steaks steak until medium, about four minutes per side. Remove from heat and let rest for five minutes. Slice the steak on a diagonal and season the slices with the lime juice and salt and pepper. Plate on top of the sauce. This is a great sauce since it has absolutely no fat. You can add some butter in the blender to make it a little creamier but if not it is a great, healthy accompaniment.