Season ground lamb with 1 teaspoon kosher salt and 1/2 teaspoon black pepper; form into 30 (1-inch-thick) patties. Combine yogurt, lemon juice, and a pinch each of kosher salt and black pepper. Slice mint leaves into thin ribbons. Grill lamb patties for 1-2 minutes per side. Warm slider buns. Place a patty on each bun; top with a dollop of yogurt mixture, and sprinkle with mint ribbons.