In a large skillet or Dutch oven with a tight-fitting lid, heat 1 tablespoon of the oil over medium-high heat. Once the oil is hot but not smoking, swirl it to coat the pan. Add the shrimp and sprinkle with ½ teaspoon of chili powder, ½ teaspoon of garlic powder, ¼ teaspoon of cumin, and ¼ teaspoon of salt. Stir gently to coat the shrimp with the spices. Cook until the shrimp are pink and fully cooked through, which takes about 2 to 3 minutes. Remove the shrimp from the skillet and set them aside on a plate.
Add the remaining ½ tablespoon of oil to the skillet. Once hot, add the onion, jalapeño, and red bell peppers. Cook until the vegetables begin to soften, which should take about 5 minutes. Stir occasionally to ensure even cooking.
Next, add the oregano, black pepper, the remaining 1 teaspoon of chili powder, 1 teaspoon of garlic powder, and ½ teaspoon of cumin to the skillet. Stir to coat the vegetables with the spices and cook for 30 seconds to allow the flavors to meld.
Incorporate the brown rice and black beans, stirring to coat them in the mixture. This step ensures that the rice absorbs all those wonderful flavors from the spices and vegetables.
Add the diced tomatoes in their juices and water. Stir everything together until well combined. Bring the mixture to a gentle boil.
Once boiling, cover the pot with a lid and reduce the heat to a simmer. Allow it to simmer for 30 minutes. This allows the rice to cook and absorb the flavors.
After 30 minutes, remove the lid and stir the mixture, scraping up any rice that may have started to stick to the bottom of the pot. Re-cover and continue to let it simmer with the lid on until the rice is tender, which may take an additional 10 to 15 minutes.
Check the rice periodically, stirring every 10 minutes to prevent sticking. If the rice begins to dry out, feel free to add a bit more water as needed.
Once the rice is cooked and tender, stir in the reserved shrimp, green onions, and cilantro. Squeeze the juice of the lime over the top to brighten the flavors.
Serve the Mexican Shrimp warm, along with any desired toppings such as additional sliced jalapeño, sour cream, or diced avocado.
