For the fries: To the warm water, add the raw sugar and whisk. Soak the fries in the sugar water for 1 hour, or up to overnight. Strain and dry off in a salad spinner. In a large pot, heat the duck fat to 175°C. Blanch 1 cup of fries at a time until cooked but not crispy, about 5 minutes. Once all batches have been blanched, raise the temperature of the oil to 195°C. Fry in batches again until golden and crispy, 3 to 4 minutes. Season with cayenne, black pepper and sea salt.
For the beurre blanc: Heat a saucepan over medium-high heat. Add the vinegar, white wine and shallots. Let boil and reduce down to 2 tablespoons of liquid. Take off the heat and let cool for about 1 minute. Put the saucepan back on the burner without turning on the heat. Throw in a few butter cubes at a time; whisk until the butter is melted. Continue until all the butter is melted. Add the tarragon, salt and some pepper. Mix. Cover, turn the heat to very low and let sit.
For the steak: Heat the canola oil in a pan over medium-high heat. Sprinkle the steaks with the salt and some pepper. Cook for 3 1/2 minutes per side for medium-rare. For the last minute of cooking, add the butter and melt. Remove the steaks from the heat, tent and let rest for 5 minutes. Place the steaks and fries on plates and top with some beurre blanc.