Step 2Combine low-fat Greek yogurt, fresh dill, scallion, and 1/4 teaspoon each salt and pepper.
Step 3Cut salmon fillet into 4 thin pieces, season with 1/4 teaspoon each salt and pepper and cook on medium in oil until opaque throughout, 1 to 2 minutes per side.
Step 4Spread yogurt mixture over 4 thick slices toasted bread and top with lettuce, sliced tomato, salmon, crisp bacon, and 4 more slices toasted bread. Serve with cucumber salad if desired.