Shrimp Tacos:

1. Preheat a skillet over medium-high heat on the stovetop.
2. In a mixing bowl, add the shrimp and lime juice.
3. Toss the shrimp while sprinkling evenly with 1/8 cup of Cajun Black seasoning and 1 teaspoon of Pacific Flake Sea Salt, coating the shrimp evenly.
4. Coat the heated skillet with avocado oil.
5. Add the seasoned shrimp to the skillet, making sure they lay flat.
6. Turn the shrimp every 3-4 minutes until they are cooked through.

Pico de Gallo:

1. In a medium bowl, combine the finely chopped white onion, jalapeno, and 3/4 tsp of Himalayan Pink Salt.
2. Squeeze the juice from the lime over the mixture and mix well.
3. Allow the onion and jalapeno mixture to marinate for 5-10 minutes.
4. Add the chopped tomatoes and cilantro to the bowl and toss to combine.
5. Let the Pico de Gallo sit for 15-30 minutes to allow the flavors to meld. Adjust the seasoning with additional salt and/or lime juice to taste.

Pickled Red Onion:

1. Peel the red onions and cut them in half. Slice into half rounds.
2. Place the sliced onions in a glass container or mason jar.
3. In a saucepan, heat the white vinegar, water, and granulated sugar on medium heat until the sugar dissolves.
4. Pour the liquid mixture over the onions, ensuring all the slices are submerged.
5. Allow the pickled red onions to cool to room temperature, then cover, and refrigerate for at least 30 minutes before serving.

To Serve:

1. Warm the corn tortillas in a skillet with a thin layer of avocado oil until they brown slightly and bubbles form.
2. Arrange the cooked shrimp, Pico de Gallo, pickled red onions, crumbled Cotija cheese, and lime wedges separately as a taco bar.
3. Encourage your guests to build their shrimp tacos by adding their desired toppings to the tortillas.
4. Offer Greek yogurt as a "sour cream" substitute for those who find the dish too spicy.
5. Enjoy the delicious and customizable shrimp tacos!