To make pickled red onion: in a bowl, combine the red onion with 2 tablespoons of lime juice and 1 teaspoon of salt, stir and refrigerate for at least one hour.
Dice the avocado and strawberries in similar sizes (0.5 cm cubes); in another bowl, mix with the remaining lime juice. Season the fish to taste.
Heat the vegetable oil in a large pan until it is almost fuming; sear the fish on both sides until brown and cooked. (approximately 2-3 minutes per side, depending on the fish’s thickness).
Place the tortillas and cover each with 1 tablespoon of sour cream, 1 tilapia fillet, 1/2 tablespoon of jalapeño, and 1 tablespoon of pickled red onion.
Pour strawberry and avocado mixture equally on each taco; serve immediately.
