To cook the shrimp: In a medium bowl whisk together olive oil, garlic, cumin, chili and onion powders, and salt. Add in shrimp and toss to coat completely. Cover and refrigerate for for at least 10 minutes or up to 24 hours. Heat a large heavy-duty or cast iron skillet on high heat for 2 minutes. Add the olive oil and shrimp. Cook shrimp in a skillet on medium-high heat until pink and cooked through, about 5 minutes.
To assemble: Divide brown rice into 4 meal prep containers (1/2 cup each). Top with 5 shrimps, a scoop of black beans, corn, tomatoes, a sprinkle of cheese, cilantro and a slice of lime. Cover and refrigerate for a max of 4 days.
To serve: Heat bowls in the microwave for 2 minutes or until heated throughly. Drizzle with lime juice and top with salsa, sour-cream or gucamole if desired.
Cook brown rice according to package directions before getting started on the shrimp so it cooks while you are preparing the shrimp.