Preheat oven to 275 degrees. Place a wire rack on a baking sheet.

Make pickled cucumbers. Pour mirin into a small pot and bring to a boil over medium-high heat. Remove from heat and add rice vinegar, lemon juice, and sugar. Stir until sugar is dissolved. Pour liquid over sliced cucumbers and fresno and let sit for at least 30 minutes or overnight.

Combine coarsley ground black pepper, ground white pepper, and ground Szechuan pepper in a small bowl. Season steak with peppercorn mixture and salt on both sides. Let sit at room temperature for 30 minutes.

Heat 1 tablespoon oil in a large saute pan over medium heat. Add sliced shallots and season with salt. Cook until deep golden brown and caramelized, stirring occasionally, about 20-25 minutes. If the pan becomes too dry, add 1-2 tablespoons of water.

Add garlic, ginger, and black beans to pan. Saute for 1 minute or until aromatic. Remove from heat and transfer to a blender along with cilantro, rice vinegar, honey, soy sauce, and sesame oil. While the blender is running, slowly add olive oil until well combined. Set aside.

Place steak on prepared baking sheet with wire rack. Roast in oven for 15-25 minutes or until desired degree of doneness. Cook steak until 90-95 degrees for medium-rare and 100-105 degrees for medium. Remove from heat. Brush caramelized shallot black bean sauce on both sides of steaks.

Heat 1 tablespoon oil a cast iron pan over medium-high heat. Lay steak in pan and sear for 2 minutes or until browned. Flip over and sear for another 1-2 minutes or until browned. Remove from heat and slice steak across the grain.

Lay lettuce leaves on serving plater and arrange sliced steak on top. Top with fresh mint and cilantro and serve with pickled cucumbers and extra caramelized shallot black bean sauce on the side.