Preheat your oven to 400°F (200°C). Slice the fennel bulb thinly and spread it on a baking sheet lined with parchment paper.
Rub the salmon fillets with salt, pepper, and a little grated orange zest to enhance their flavor. Place the fillets skin-side down on top of the fennel slices.
Zest both oranges and squeeze out the juice, then drizzle the juice over the salmon and fennel for a citrusy aroma. Spread thin slices of ginger around the fillets for a fragrant touch.
Drizzle olive oil over everything and sprinkle a bit more salt and black pepper to taste. Use your hands or a brush to evenly distribute the seasonings.
Place the baking sheet in the oven and roast for about 15-20 minutes, until the salmon is opaque and flakes easily, and the fennel is tender with slightly caramelized edges.
Remove from the oven and let the salmon rest for a few minutes. Garnish with a little extra citrus zest if desired, and serve the salmon alongside the roasted fennel and caramelized ginger slices.