Preheat oven to 400˚F.

Heat a the oil in a large skillet over medium-high heat. Add the onion and poblano pepper, and sauté 5-8 minutes, until tender and golden. Add the shrimp to the skillet and sprinkle with salt. Cook, stirring frequently, 2-3 minutes, just until shrimp are barely cooked through. Transfer the shrimp, onion, and pepper to a large mixing bowl, then cover and refrigerate for 10-15 minutes.

Heat the corn tortillas in a hot, dry skillet until soft and pliable. Add 1 1/2 cups of the shredded cheese to the shrimp mixture and fold to combine, then assemble the enchiladas. Spoon about 1/8 of the shrmp and cheese mixture onto a warm tortilla. Roll up like a tube, and place seam-side-down in a 9x13" baking dish. Repeat with remaining tortillas and filling. Pour the enchilada sauce over the filled tortillas, using the back of a spoon to completely cover them in sauce. Sprinkle with the remaining shredded cheese, and bake until heated through, the sauce is bubbling, and cheese is melted and golden, about 15 minutes. Serve hot.