01 - Rinse the Japanese rice under cold water until the water runs clear. Combine rice and water in a pot or rice cooker. Cook according to rice cooker instructions or bring to a boil, then cover and simmer on low heat for 15 minutes. Let rest for 10 minutes before serving.
02 - In a small bowl, combine rice vinegar, sugar, and salt. Add cucumber and carrots, toss well, and let marinate for at least 15 minutes.
03 - Pat fish fillets dry and brush with soy sauce and mirin. Heat oil in a nonstick skillet over medium heat. Grill fish, skin-side down, for 3-4 minutes per side until cooked through and golden. Set aside.
04 - Beat eggs with soy sauce. In a small nonstick pan, cook scrambled eggs or make a thin omelet, then slice into strips.
05 - In each bento box or plate, add a portion of rice (sprinkle with sesame seeds and nori strips, if using). Arrange grilled fish, pickled vegetables, egg, avocado slices, steamed edamame, and apple or fruit on the side.
06 - Serve immediately, or let cool, cover, and refrigerate for a portable breakfast.