Balsamic Reduction:
In a small saucepan, combine the balsamic vinegar, red wine, and sugar.
Bring to a boil and cook for 12 minutes or until the glaze has thickened, stirring occasionally; it will thicken significantly as it cools.
Yield: about 1/3 cup (80 ml). Set aside.
Fennel Confit:
Prepare the confit while the reduction is cooking.
Melt the butter in a saucepan over medium heat.
When the butter starts to foam, add the fennel, red onion, orange juice, and sugar, and stir to combine.
Bring to a boil, then reduce the heat to low.
Cover and cook for 10 minutes or until the fennel is tender.
Remove the lid, increase the heat to medium, and cook for an additional 8 minutes, stirring occasionally, until the fennel is caramelized. Season with salt and pepper.
Salmon:
Heat a non-stick skillet over high heat.
Add the oil, then the salmon, skin side down (if it has skin). Season with salt and pepper.
Cook for about 2 minutes or until golden brown, then flip the salmon and cook for an additional 2 minutes. Cover the skillet and cook for 3 to 5 minutes, or until the fish is cooked through.
Divide among 4 plates. Serve with the fennel confit and drizzle with the balsamic glaze.