First, preheat a cast-iron skillet over medium. While you’re waiting, lightly roll the chiles to release some spicy flavor from the seeds and veins.
Add the chiles to the hot skillet and cook until you see blisters forming on all sides. Make sure to stir them frequently so each side cooks evenly, about 5-6 minutes. Transfer the chiles to a bowl and set that aside.
Add 1 tablespoon of olive oil, then the sliced onion. Sauté until translucent and slightly browned, about 4 minutes. Add the minced garlic and chiles back in.
Continue cooking for another 2-3 minutes, or until the onions are caramelized to your liking. Lastly, mix in the lime juice, soy sauce, and salt to taste.
Serve immediately, at room temperature, or chilled with any dish you can think of (tacos, toast, quesadillas, tofu scramble, etc.). Happy eating!