Preheat the oven to 350 degrees F and preheat a fryer or 3 inches oil in a medium heavy-bottomed pot to 350 degrees F. Line a plate with paper towels.
Layer the bacon on a small sheet pan greased with 1 tablespoon canola oil. Bake until very crispy, 10 to 12 minutes. Remove and set aside until ready to use.
Using a mandoline, carefully slice the Brussels sprouts paper-thin and sprinkle with salt.
Drop the Brussels sprouts into the oil and cook, continuously moving them around, until golden brown, 3 to 4 minutes. Drain thoroughly on the paper towels. Add the leeks to the oil and cook for 3 to 4 minutes. Drain and add to the paper towels. Dice the bacon into small bites.
Place the Brussels sprouts and leeks in a shallow dish and season with salt. Drizzle with the balsamic, then top with the crispy bacon and serve.