Cut the sushi-grade ahi tuna into 1/2-inch cubes and place them in a medium glass bowl.
In a small jar, whisk together the coconut aminos, toasted sesame oil, grated ginger, and minced garlic until emulsified.
Pour the marinade over the tuna, toss gently to coat, and let it chill in the refrigerator for 15 minutes.
In another bowl, combine the diced mango, diced pineapple, finely diced red onion, chopped cilantro, and lime juice to create the tropical salsa.
Place the warm cooked brown rice in the center of a serving bowl.
Arrange the marinated tuna, sliced cucumber, shelled edamame, and avocado slices around the rice base.
Season the entire bowl with the sea salt and black pepper before serving immediately while fresh.