Preheat the grill to medium-high heat.

In a small bowl, mix olive oil, garlic powder, onion powder, smoked paprika, salt, and pepper. Rub the mixture all over the flank steak.

Grill the steak for about 5-7 minutes on each side, or until it reaches your desired doneness. Remove from the grill and let it rest for 5 minutes before slicing.

While the steak is resting, toss the zucchini slices with a little olive oil, salt, and pepper. Grill the zucchini for about 3-4 minutes on each side until tender and slightly charred.

In a small bowl, mix together sour cream, lime juice, and chopped cilantro to create the creamy sauce.

To assemble the bowls, divide the cooked brown rice among four bowls. Top each with sliced steak, grilled zucchini, cherry tomatoes, and avocado. Drizzle with the creamy sauce.