The key to the best latkes is patting the potato-and-onion mixture very dry on paper towels before adding eggs and matzo meal. Get everything ready, including the salt for sprinkling on the cooked latkes, before you grate the potatoes and onion.
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.