This spicy steak appetizer packs big flavor into a little bite.
Process garlic, bay leaves, jalapenos, chile powder, salt, and 2 tablespoons vinegar in a blender until a paste forms. Transfer to a mixing bowl. Add herbs. Whisk in remaining 2 tablespoons vinegar and the oil until smooth.
Put steak in a baking dish, and coat both sides with marinade. Refrigerate steak, covered, overnight.
Heat a grill pan or grill to medium-high heat. Scrape marinade from steak. Grill steak, turning once, to desired doneness, 6 to 7 minutes per side for medium-rare.
Let steak rest 10 minutes. Cut against grain at an angle into 1/8-inch-thick slices. Place 2 to 3 slices on each plate. Top with salsa and leeks; garnish with peppercorns.