Combine diced onion, lime juice and ¼ tsp kosher salt in a small bowl. Set aside.
Heat a medium-sized non stick skillet over medium-high heat. Add in avocado oil and swirl around the pan. Add the shrimp and sprinkle with garlic powder, onion powder, black pepper and ¼ tsp kosher salt. Saute until shrimp just turns pink, then remove from the heat and set aside. In a large mixing bowl, add in diced roma tomatoes (seeds removed), small dice english cucumber, diced celery, finely diced jalapeno (seeds removed) and sprinkle it all with 1 tsp kosher salt.
Add in shrimp. Stir.
Add onions and tomato juice.
Top with diced avocado. Gently push avocado into the juice. Top with chopped cilantro and allow to chill for at least 1 hour.