In a small bowl, stir to combine all ingredients until well-combined. Cover and refrigerate until ready to serve.
For Sliders: Cut salmon into ½- to 1-inch pieces, spread in a single layer on a plate and place in the refrigerator for 10 minutes. Transfer to a food processor and pulse 7 to 8 times or until coarsely minced (do not over process).
In a large bowl, toss to combine the remaining ingredients, except the mustard and egg, until well combined. In a small bowl, beat the egg with the mustard, add to the bread crumbs along with the fish and toss until well blended. Form into patties about the same size as the bun. cover and refrigerate for 1 hour. Patties can be made a day ahead.
Set up grill for direct cooking over medium-high heat. Brush and oil grate well before cooking. Cook 3 to 4 minutes per side until done. (Be careful not to overcook as burgers will dry out.) Serve hot on slider buns dressed with watercress, smoked tomato, and Green Olive Aïoli.
Recipe by Grilling Outdoor Recipes powered by Bull Outdoor Products at https://blog.bullbbq.com/salmon-sliders-with-green-olive-aioli/