Season salmon filets with salt and rub with chinese five spice. Let sit at room temperature for 1 hour.
Heat sauté pan on Medium High, melt the butter and add olive oil. Sauté the fillets skin side down until crisp (3minutes). Turn it over and sauté for another 1-2 minutes. Set aside. Note: if you portion the filet ahead and they are thick and tall, do each side for 20-30 seconds before flipping to skin side up.
Reduce heat to low and in the pan, combine maple syrup, lemon juice, tamari, minced garlic and tarragon. Bring to simmer. Let the sauce reduce into half, or until it gets thick and syrupy.
Put the salmon skin side up back into the reduced sauce and tilt the pan to coat the fillet and sides with the syrup.
Serve immediately.