Preheat oven to 300°F.

Shred potatoes using a coarse grater or food processor.

Wrap potatoes in a kitchen towel and squeeze out excess liquid in batches.

Transfer to a large bowl.

Repeat shredding and squeezing process with onion, then add to the bowl with potatoes.

Mix in eggs, flour, salt, and pepper into the potato mixture.

Heat 2 tablespoons of vegetable oil in a large skillet over medium-high heat.

Drop potato mixture by 1/4 cupfuls into the skillet in batches.

Flatten to 3-inch rounds.

Fry latkes until golden brown on bottom, about 4 minutes per side, adding more oil as needed.

Transfer latkes to a rimmed baking sheet and keep warm in the oven.

Mix crème fraîche and chopped fresh tarragon in a small bowl to blend.

Divide smoked salmon among the latkes.

Top each latke with a dollop of tarragon crème fraîche, then caviar.