Drain the tuna and flake. Squeeze the lemon into the tuna and mix. Add the mayonnaise and mash slightly. Wash the celery, pepper and dill. Pat the dill between 2 pieces of paper towel to dry. Chop the celery and pepper into bite-size pieces; mix into tuna. Snip the dill, using a pair of kitchen shears, into the salad and mix well.
Spread onto the sandwich bread to make 4 sandwiches. Using star-shaped cookie cutters, cut out 4 sandwiches.