PUT A HEALTHY PINCH OF SEA SALT AND SEVERAL GRINDINGS OF PEPPER IN THE BOTTOM OF A BOWL. WHISK IN THE JUICE OF 1 LEMON.
CHOP 3 SCALLIONS AND ADD TO THE BOWL.
PEEL A FEW INCHES OFF ONE END OF THE HORSE RADISH. USING THE NEXT TO FINEST SIDE OF BOX GRATER, GRATE ABOUT 3/4 CUP ONTO A PIECE OF WAXED PAPER. DUMP THE GRATED HORSE RADISH INTO THE BOWL.
ADD ABOUT 3/4 CUP OF CRÉME FRAÎCHE. TASTE. IF IT'S TOO HOT ADD MORE CRÉME FRAÎCHE. IF YOU WANT IT HOTTER GRATE IN MORE HORSE RADISH.
ADD THE SMOKED TROUT FILLETS. BREAK UP WITH A FORK AND FOLD INTO THE HORSE RADISH MIXTURE.
THINLY SLICE THE RADISHES AND FOLD INTO THE TROUT SALAD.
PUT A MOUND OF SALAD ON EACH PLATE. TUCK THE TREVISO OR ENDIVE LEAVES UNDER THE SMOKED TROUT.
SCATTER WITH FRESH DILL AND/OR CHOPPED CHIVES.
SERVES 6-8