Preheat the oven to 350 degrees
De-stem the arbol chiles and shake out the seeds. Discard the seeds and stems.
De-stem the cascabel chiles, remove the seeds and veins. Reserve the seeds.
Place the chiles on a cookie sheet on the center rack in your oven and toast for 4 minutes. Remove from oven and set aside.
Move an oven rack to the top position in your oven and preheat the broiler on high. Core your tomatoes and broil until all sides are blackened (turning once halfway through).
Toast the reserved cascabel seeds over medium heat in a cast iron skillet stirring and turning constantly to prevent burning. They're done when they turn a deep golden brown. Be careful not to burn them, they'll add a bitter flavor to your salsa.
Place the garlic cloves in a shallow dish with just enough water to cover and microwave for one minute. Drain.
Throw all of the dry ingredients in a blender and pulse until the chiles are well broken down, but not powdered. Add the balance of the ingredients and blend for about two minutes.
Let stand for about 15 minutes before serving.