Instructions

• For the sauce: Grate the cucumber on the large-holed side of a box grater. Place the grated cucumber in a fine-mesh strainer and drain for a minute or two, pressing out as much liquid as possible.
• Stir together the grated cucumber, yogurt, oil, lemon juice, garlic, parsley, salt and pepper in a medium bowl. The yield is about 1 cup. Cover and refrigerate until ready to use (and up to 4 days).
• For the burgers: Place the bread in the food processor and pulse to make fine crumbs. (The yield should be about 1 1/2 cups.) Transfer them to a large mixing bowl.
• Cut the salmon into large chunks, then transfer to the food processor; pulse until chopped but some pieces still remain visible, 10 to 15 pulses; add to the bowl with the bread crumbs.
• Add the scallions, celery, dill, Dijon mustard, lemon juice, egg white, salt and pepper to the bowl, mixing to combine. Form this mixture into 4 equal patties and place them on a plate. Cover and refrigerate for 10 minutes to set.
• Preheat a grill pan over medium-high heat. Once it is hot, grease it with cooking oil spray; add the salmon patties and cook for about 3 minutes per side or until just cooked through.
• Serve with the sauce, on whole-grain buns or with lettuce leaves (to use as wraps).