Preheat oven to 400 degrees. Prepare rice as directed on package (1 cup dry rice) either before preparing fish to bake, or right after placing it in the oven.
Lay out a large piece of foil and place fish onto it. Slice onion thinly, add to fish along with tomatoes. Slice lemon and lime thinly, place on top of fish medley; drizzle with olive oil, season with 1/2 tsp salt and 1/4 tsp pepper. Fold and seal foil. Place into heated oven and bake for 12-15 minutes. If desired, yet this may change cooking time, place fish-filled foil onto a baking sheet before placing into oven.
While fish bakes, toss asparagus with olive oil, 1/4 tsp salt and 1/4 tsp pepper; sauté in a large skillet for 6-8 minutes, timing depends on thickness and desired doneness. Dice melon while asparagus sautés.
Serve fish on top of brown rice with asparagus.