Bring the water to a boil in a small saucepan, add the ancho chiles and return to a boil. Remove the pan from the heat and let the chiles stand in the water for 5 minutes. Drain, reserving 2 tablespoons of water. Transfer the chiles with the water to a blender and purée.
In a large bowl, use your hands to mix the masa, bone marrow and flour together. Add the puréed chiles and knead until the mixture is smooth.
Shape the masa mixture into tiny patties 2-3 in (5-7.5 cm) in diameter and 1/8 in (3 mm) thick. Heat 1/2 in (1 cm) oil in a skillet and fry the patties in batches, using a slotted spoon remove them from the skillet. Drain on absorbent paper.
Combine all the salsa ingredients in a small bowl. Arrange the patties on a platter and place a dab of salsa on each.