Begin by prepping the arbol chiles. Carefully remove the stems and shake out some seeds, adjusting to your preferred spice level.

Heat a skillet over medium heat. Add the chiles and toast for 2-3 minutes until fragrant and slightly darkened.

In a pot, bring water to a boil and add your toasted chiles. Remove from heat, cover, and let soak for about 15 minutes.

In a separate skillet, heat olive oil and sauté chopped white onion until translucent, about 3-4 minutes. Stir in minced garlic for an additional 1-2 minutes.

Add chopped Roma tomatoes to the skillet and soften for about 5 minutes.

Transfer the mixture to a blender, add soaked chiles, lime juice, and salt. Blend until smooth.

If too thick, add a teaspoon of reserved chile soaking water at a time until desired consistency is reached.