Rinse the brown rice under cold water until the water runs clear.
In a medium saucepan, combine the rinsed brown rice and 2 cups of water. Bring to a boil over high heat.
Once boiling, reduce heat to low, cover, and simmer for 40 minutes or until rice is tender and water is absorbed. Remove from heat and let stand covered for 5 minutes.
While the rice cooks, heat olive oil in a large skillet over medium-high heat.
Add the diced onion and sauté for 3-4 minutes until softened.
Add the minced garlic and cook for 1 minute until fragrant.
Add the ground beef to the skillet, breaking it apart with a spatula. Cook until browned and no longer pink, about 6-8 minutes.
Drain any excess fat from the skillet.
Stir in chili powder, ground cumin, smoked paprika, dried oregano, cayenne pepper, salt, and black pepper. Cook for 2 minutes, stirring frequently.
Add the black beans, corn kernels, and diced red bell pepper to the skillet. Cook for an additional 3-4 minutes until vegetables are heated through but still crisp.
Fluff the cooked brown rice with a fork and divide it evenly among four bowls.
Top each bowl of rice with the beef and vegetable mixture.
Garnish each bowl with halved cherry tomatoes, chopped cilantro, shredded cheddar cheese, and a dollop of Greek yogurt.
Serve each bowl with a lime wedge to squeeze over just before eating.