While the potatoes cook make the salsa. Place the tomatoes, onion, and chiles de árbol in a saucepan, cover with water, and bring to a boil. Simmer until the tomatoes are soft, about 10 minutes.
3 large tomatoes, ¼ white onion, 3 to 4 dried chiles de árbol
Transfer the tomatoes, onion, and chiles to a blender with the garlic, pepper, oregano, and chicken bouillon. Blend until smooth, adding up to ½ cup of the cooking water for a pourable salsa. Season with salt. Keep warm.
1 garlic clove, 1 teaspoon chicken bouillon powder, 1 teaspoon salt, ½ teaspoon black pepper, ½ teaspoon dried Mexican oregano