Preheat a comal or griddle pan to medium/low heat for 5 minutes. Add all the chiles, pepitas and ajonjoli to the comal or griddle. When toasting chiles, seeds or nuts, you should never leave them unattended because they can burn easily. Toast them for about 5 to 7 minutes, turning as needed.
When the peppers become aromatic and blacken in some spots, they are ready. The sesame seeds and pepitas will also turn slightly brown in color. If you let any of them go too long, they will taste bitter. Before removing ingredients from comal, add the oregano for a minute.
Transfer all of the ingredients to the blender. Add all of the remaining ingredients listed. Blend on high until smooth. You will have to push ingredients down with a spatula a couple of times to make sure it all blends well. Taste for salt. If you want to thin out the salsa a little more, just add a little more water.
