Grate potatoes and onion through large holes on a box grater. Pat grated potatoes and onion dry with paper towels.
Place potatoes and onion in a large bowl. Stir in lightly beaten eggs and next 3 ingredients.
Drop potato mixture by heaping tablespoonfuls into hot canola oil in a large, deep skillet over medium-high heat; cook 2 to 4 minutes on each side or until golden brown. Drain latkes on paper towels, and sprinkle with kosher salt to taste, if desired. Top each latke with 1 tsp. Salmon-Olive Relish. Garnish, if desired. Serve immediately.
Note: To keep latkes warm before topping with relish, place on a wire rack on a baking sheet. Place in a 250° oven up to 30 minutes.