Cook the brown rice according to package instructions and set aside to cool slightly.
Dice the ahi tuna into bite-sized half-inch cubes using a sharp knife.
In a medium bowl, whisk together the tamari, sesame oil, grated ginger, and sea salt.
Fold the tuna cubes into the marinade and let sit in the refrigerator for 10 minutes.
Prepare the tropical salsa by combining diced mango, pineapple, red onion, cilantro, and lime juice in a small bowl.
Slice the avocado and cucumber into thin pieces.
Assemble the bowl by placing the rice at the bottom, followed by the marinated tuna, edamame, cucumber, and avocado.
Top with the tropical salsa and serve immediately.