Prepare Latke Mixture: Grate russet potatoes and yellow onion. Soak in salted water for 20-60 minutes. Drain and squeeze moisture. Combine with beaten egg, matzo meal, kosher salt, and black pepper.

Cook Latkes: Heat vegetable oil in a skillet. Drop spoonfuls of latke mixture into oil, cook for 6-8 minutes until golden, flip, and cook for another 6-8 minutes. Drain on paper towels.

Poach Eggs: In a saucepan, simmer water with vinegar. Create a whirlpool, crack eggs one at a time, and poach for 4½ to 5 minutes. Remove with a slotted spoon.

Make Hollandaise: Blend egg yolks, lemon juice, and salt for 30 seconds. Gradually add melted butter while blending to create hollandaise.

Assemble Dish: Place a latke on a plate, add a slice of smoked salmon, top with a poached egg, drizzle hollandaise, and garnish with chives and red onion.