For the adobo, wipe chillies clean with a wet cloth, take off stem, cut in half and remove seeds.
Heat a heavy cast-iron pan on a low to medium heat. Toast the chillies in batches, turning them and pressing down with tongs until they become fragrant, are lightly browned and the skin starts to blister – about 1 1/2 minutes. Place in a bowl and cover with water. Soak for about 30 minutes, until soft. Drain and discard water.
Blend chillies with fresh water and remaining adobo ingredients until smooth, adding more water if needed.
Pat fillets dry with paper towel, season with salt, then coat both sides with adobo marinade. Refrigerate for 30 minutes.
Heat a heavy cast-iron pan on a medium heat. Add the oil and then add fish pieces, cooking for 2 minutes. Turn over fish and cook for another 2-3 minutes until just cooked through. Allow to rest in a warm place for 5 minutes.
Place the fish on plates, squeeze over fresh lime and serve immediately.