Place quinoa in a medium saucepan and cover with chicken bone broth. Bring to a boil, then turn down the heat, cover, and simmer for 12–14 minutes, or until all of the broth is absorbed. Remove from the heat and keep covered for 5 more minutes.
Brush some olive oil on each side of the tuna steak. Sprinkle with 1/2 teaspoon Old Bay seasoning and 1/4 teaspoon ground black pepper. Set aside.
Place shrimp in a medium bowl, season with 1/2 teaspoon Old Bay seasoning and 1/4 teaspoon ground black pepper. Mix well and set aside.
Grease a cast iron griddle and heat it up over medium-high heat. Once the griddle is hot, place shrimp on it in one layer, leaving some room for the tuna steak. Cook each side of the shrimp for 2 minutes undisturbed.
One minute before the shrimp is done, place the tuna steak on the griddle, sear each side for 30 seconds.
Remove from heat, let cool and cut into cubes.
Cut avocado, onion, radish, serrano pepper, and chop cilantro.
In a small bowl, combine the dressing ingredients and mix well.
Place all ingredients in a large mixing bowl. Pour the dressing over. Mix well.