You are going to be frying the dry ingredients, each one separately, in the oil. Be sure you are working in a space with ample ventilation and that you are able to give 100% of your attention to this task (which is brief, but crucial). Be careful that none of the ingredients burn, as that would make the sauce bitter.
Heat the oil in a medium-sized sauce pan. Do not let it get hot enough to smoke or start boiling.
Place the garlic cloves, whole, into the oil and fry them for a minute or two, turning them often with a pair of tongs. Once they look toasty golden, take them out of the oil and place them into the container of a blender.
Place the chiles de árbol into the oil to fry. Use the tongs to constantly turn the chiles over so that they don´t burn on any side. Fry gently until they are golden brown, one or two minutes. Remove the chiles from the oil and add them to the garlic in the blender container.
Now take the sauce pan off the burner. Add the sesame seeds and oregano to the oil. Allow the pan to sit for a while, until the oil has cooled down enough that it can be handled without danger.
Pour the oil into the blender container and add the salt. Blend on medium high for about 30 seconds, until the chiles, their seeds, and the sesame seeds are well pulverized.
Pour your delicious chile de árbol sauce into a jar with a tight-fitting lid. Use a spoon to dish it out by drops (it is quite spicy, after all) to flavor nearly any plain savory dish such as grilled or roasted meats, soups or stews, potato or corn dishes, or anything creamy.
Store your jar of sauce in the fridge, where it will keep perfectly for at least 3 weeks.
Important: Stir well each time you use it, as the oil and the other ingredients quicklyl separate.
Variations: Once you´ve tried the sauce as written above, try substituting the sesame with a handful of peanuts, pecans, or almonds for a flavor twist.
Chile de Arbol Sauce (Salsa de chile de árbol en aceite) https://comboplate.net/chile-de-arbol-sauce/