1. Spread goat cheese evenly on bread slices, and sprinkle with black pepper. Top 12 bread slices evenly with cucumber, radishes, and salmon. Top with remaining 12 bread slices, pressing together gently.
2. Spread outside of sandwiches with softened butter. Cook in a nonstick skillet over medium heat, in batches, 2 minutes on each side or until cheese melts and bread is golden brown.