In a large bowl or gallon-sized zip-top bag, whisk together lime juice, pineapple juice, olive oil, garlic, cumin, chili powder, smoked paprika, salt, black pepper, red pepper flakes, and cilantro.
Add the steak to the marinade, ensuring it's completely covered. Seal and refrigerate for at least 2 hours, preferably overnight for maximum tenderness.
Rinse the parboiled rice under cold water for 2 minutes, rubbing the grains with your fingers to remove excess starch.
Heat butter in a large sauté pan over medium heat. Add the rinsed rice and stir for 2-3 minutes until it smells nutty and turns slightly golden.
Add minced garlic and cook for 30 seconds until fragrant, being careful not to burn it.
Pour in warm chicken broth, lime juice, and a pinch of salt. Bring to a boil, stir once, then immediately cover with a lid.
Reduce heat to low and cook for 12-15 minutes without lifting the lid until all liquid is absorbed.
Remove from heat and let sit covered for 5 minutes. Fluff with a fork and fold in fresh cilantro if using.
Remove steak from refrigerator 30 minutes before cooking to bring to room temperature.
Heat a large cast iron skillet over high heat until screaming hot. Add the steak and cook for 3-5 minutes per side for medium-rare, adjusting time based on thickness and preferred doneness.
Transfer steak to a cutting board, cover loosely with foil, and let rest for at least 5 minutes.
In the same skillet over high heat, add 1 tablespoon oil. Add onions, bell peppers, and poblano pepper. Cook for 2-3 minutes, stirring every 30 seconds, until slightly charred but still crisp. Season with salt and pepper.
Slice the rested steak against the grain into thin strips.
Build bowls by starting with garlic lime rice, adding sliced steak and charred vegetables, then topping with your favorite toppings like guacamole, pico de gallo, sour cream, black beans, and lime wedges.