Cut 2 rounds from each bread slice with 2-inch cookie or biscuit cutter; place on baking sheet. Broil until lightly toasted on both sides; cool.
Combine salmon, mayonnaise, onion, celery, lemon juice, dillweed, salt and pepper in small bowl. Top each bread round with cucumber slice and about 1 tablespoon salmon mixture. Garnish with dill sprig, if desired.
Cook's Notes
Make fresh bread crumbs from the leftover bread scraps. Tear the bread into pieces and place in a food processor or blender container. Process to form fine crumbs. Store crumbs in a zip-top plastic freezer food bag. Freeze for up to three months.