Cook the vegetables and fruit up stir-fry style. You can cook them over the grill in cast iron so you can take advantage of grilling to draw out the best flavor in the tuna. Remember, if you’re buying tuna from a reputable and fresh source, tuna can be at its best when served a bit rare. Add more ginger to taste, and if you’re salting to taste, try low-sodium soy sauce for great added umami.