Beat the cream cheese, mayonnaise and lemon juice til smooth.
Cut about 9 thin slices of cucumber. Then cut each slice in half to get 18 half slices. The exact number you will need will depend on the size of your cucumber.
Cut the remaining cucumber in half lengthwise. With a vegetable peeler make 4-6 long thin strips of cucumber.
Cut off some tips of fresh dill fronds.
Reserve about 1/2 cup of the cream cheese mixture. Spread the remaining cream cheese evenly over the top and sides of the loaf.
Using a piping bag and tip, take the reserved 1/2 cup of cream cheese mixture and pipe florettes around the upper edge of the loaf.
Position cucumber half rounds along the base of the sandwich loaf. Curl the long strips of cucumber and center them along the length of the loaf. Position dill fronds decoratively like branches coming off the cucumber curls.
Refrigerate until ready to serve.
To serve cut about a 1" slice at a time. Support the slice with a cake server so it doesn't fall apart when transferring to a plate.