Adobo Fish Tacos with Grilled Pineapple Salsa

2 oz or 3 ancho chiles rinsed, stemmed and seeded
1/2 cup white onion coarsely-chopped
2 garlic cloves peeled
1 tablespoon dried oregano
1/2 cup apple cider vinegar
1 teaspoon brown sugar
3/4 teaspoon kosher or sea salt
2 tablespoons vegetable oil
1 pound of mild and firm fish fillets like snapper striped bass, rock fish, snook or tilapia
4 pineapple slices
1 jalapeño or serrano chile chopped, or to taste
3 tablespoons chopped cilantro
1 tablespoon freshly squeezed lime juice or to taste
1 tablespoon olive oil
To taste kosher or coarse sea salt
corn tortillas

Cover the chiles with boiling hot water and let them soak for 10 minutes. Pace the chiles along with 1/2 cup of soaking liquid, onion, garlic, oregano, vinegar, sugar and salt in the blender. Purée until smooth.
In a saucepan set over medium heat, heat the oil. Once hot, pour the sauce into the oil; cover the saucepan, leaving it slightly open, and let the sauce season and thicken for 6 to 8 minutes, stirring here and there. Remove from the heat.

Baste the fish fillets with the adobo sauce; you may refrigerate them and let them marinate for up to 24 hours.
In a large skillet coated with oil and set over medium-high heat, cook the fish for about 3 to 4 minutes per side.

Heat a grill pan, a grill or a nonstick skillet over medium heat until hot and lightly coat with safflower or corn oil. Cook the pineapple slices for about 4 minutes per side until they are slightly charred. Remove from the heat, once cool enough to handle cut into bite-size chunks. Place in a mixing bowl and toss with the cilantro, chile, lime juice, oil and salt to taste.

Place the warm tortillas, the pineapple salsa and the fish on the table, then assemble the tacos!