To make the burgers: place the salmon, onion, scallion, lemon juice, salt and peper in a food processor and process until all the ingredients are blended.Divide the salmon mixture into 4 patties.
Place all the ingredients in a food processor or blender and blend until smooth.
Transfer to a bowl, cover, and refrigerate until ready to serve.
Heat a pan over medium high heat.
Place 1 bun bottom on each plate, top with lettuce, red onion, and 1 patty.
Spread the basil mayo on top of the patty and cover with the bun top.