1. Season steak with salt and pepper. Drizzle soy sauce and white vinegar over steak to coat. Add lime, cilantro, and rub all over both sides. Marinate 2 hours.
2. Preheat the grill to high heat.
3. Coat the steak with olive oil.
4. Grill until nicely charred on both sides and a probe thermometer registers an internal temperature of 130 F (54 C).
5. When ready, loosely cover and rest for 10 minutes.
1. Fill a large pot with water and bring to a boil. Add the fingerling potatoes and boil for 12 minutes. Remove and allow the potatoes to cool at room temperature. Cut in half.
2. Heat oil in a large cast iron skillet over medium-high heat. Add the tomatoes, cut side down, then the rounds of red, yellow, orange, and green peppers, skin side down. Season with salt and pepper. Allow to char, without moving, for 1 minute.
3. Flip the veggies once and char the other side, then remove and keep warm.
4. Heat duck fat in the skillet over medium heat. Sear the potatoes, cut side down, for 6 minutes, then flip and cook for 4 minutes.
5. Transfer the seared potatoes to a bowl and toss with salt, pepper, cilantro leaves, and parsley.
6. Keep warm.
1. Heat olive oil in a skillet over high heat, add red onions and garlic and cook 1-2 minutes until starting to brown.
2. Reduce heat to medium. Add vinegar and cook for 1 minute.
3. Add beef stock and soy sauce, and bring to a boil and reduce for 12-15 minutes, or until lightly syrupy.
4. Remove from heat and stir in cilantro, parsley, and lime. Season with salt and pepper.
5. Keep warm.
1. Plate 1 round of each color pepper in in a broken line top to bottom in the center of white plate.
2. Place 2 tomato wedges where desired, with space in between.
3. Place 2 fingerling halves where desired.
4. Cut the rested flank steak into thin slices, fold 2-3 slices and arrange on the dish on and around the peppers and tomato.
5. Drizzle sauce over and between the veggies.
6. Garnish with scallions.