Clean the chiles, making sure all seeds and stems are removed. Place them in a pot along with the chopped onion, sliced tomato, ground cumin, and minced garlic. Add water to cover the chiles and bring to a simmer for 15 minutes.
Transfer all the ingredients to a blender, add ½ cup of the water it was simmered in, and blend until smooth. Set aside.
In a sauté pan, heat the olive oil over medium-high heat. Add the shrimp and Chef Merito® Fish Seasoning, and cook for 1 minute.
Add the chile sauce to the pan, mix well, and cook for 4 to 5 minutes over medium-low heat.
Spoon the shrimp onto warm tortillas and top with guacamole, fresh cilantro, and sliced red radish.