Rinse salmon; pat dry with paper towels. Put 1/2 of the salmon, bread crumbs, egg white, green onion, roasted red bell pepper, parsley, 1 1/2 teaspoons baharat, and salt in a blender; blend until combined.
Transfer blended mixture to a bowl. Chop remaining salmon into 1/2-inch pieces and add to the bowl. Mix well until soft. Shape into four 3/4-inch-thick patties.
Preheat broiler. Arrange patties on a foil-lined baking sheet.
Broil 4 to 5 inches from heat source, turning once, until an instant-read thermometer inserted into the center registers 160 degrees F (71 degrees C), 14 to 18 minutes.
For the aioli, stir together mayonnaise, garlic, lemon juice, lemon zest, and remaining 1/4 teaspoon baharat in a small bowl.
Garnish salmon cakes with black pepper and serve with aioli.