The piquant flavor of capers perfectly accents the salmon for these colorful appetizers.
For avocado spread, in a small bowl mash avocado. Stir in capers, lemon juice, and garlic. Cover surface of spread with plastic wrap. Chill in the refrigerator for up to 2 hours.
To tote, place salmon, watercress, and onion in separate containers. Pack along with avocado spread in an insulated cooler with ice packs.
To serve, let each person layer avocado spread, salmon, watercress, and onion slices on crackers. Makes 12 servings.