01 - Rinse rice under cold water. In a saucepan, combine rice, water or broth, and a pinch of salt. Bring to a boil, reduce heat to low, cover, and simmer for 15 minutes. Remove from heat, let stand 5 minutes, then fluff with a fork. Stir in lime juice and cilantro if using.
02 - In a bowl, toss sliced steak with olive oil, chili powder, cumin, garlic powder, smoked paprika, salt, and pepper until evenly coated.
03 - Heat a large skillet or grill pan over medium-high heat. Cook steak slices in a single layer for 2-3 minutes per side, until browned and just cooked through. Remove from heat and tent with foil to keep warm.
04 - In a saucepan, melt butter over medium heat. Whisk in flour and cook for 1 minute. Gradually whisk in milk until smooth. Cook, stirring, until thickened for 2-3 minutes. Lower heat and add cheeses, smoked paprika, cayenne if using, and salt. Stir until cheese is melted and sauce is smooth.
05 - Divide rice among 4 bowls. Top with steak slices, black beans, tomatoes, corn, avocado, and any other desired toppings. Drizzle generously with warm queso sauce. Garnish with cilantro and a wedge of lime.