Start by combining the soy sauce, honey, rice vinegar, sesame oil, minced garlic, and grated ginger in a small bowl. Whisk until well blended, then place the flank steak or sirloin in a resealable plastic bag or shallow dish. Pour the marinade over the steak, seal or cover it, and let it marinate in the refrigerator for at least 30 minutes, up to 2 hours for deeper flavor absorption.

While the steak marinates, slice the zucchinis into ½ inch thick rounds. In a mixing bowl, toss the zucchini with olive oil, garlic powder, onion powder, smoked paprika, salt, and pepper.

Preheat your grill to medium-high heat, aiming for around 375°F (190°C). Once the grill is hot, remove the steak from the refrigerator and let any excess marinade drip off. Place the marinated steak directly on the grill grates. Cook for about 4-5 minutes on each side for medium-rare.

After the steak is fully cooked, transfer it to a cutting board and let it rest for about 5 minutes. While it's resting, add the prepared zucchini rounds to the grill. Grill the zucchini for 3-4 minutes on each side until they are fork-tender.

Start with a base of cooked brown rice or quinoa, creating a hearty layer. Then, layer on the sliced grilled steak, grilled zucchini rounds, halved cherry tomatoes, and avocado slices.

Drizzle some of the reserved marinade sauce over the top of your assembled bowls, infusing extra flavor. If you like, sprinkle sesame seeds on top for a delightful crunch. Garnish with fresh cilantro and serve immediately with lime wedges on the side.