Preheat the oven to 425 degrees F and line a large baking sheet with parchment paper.
Place the sweet potato wedges in a bowl and toss with 2 tablespoons olive oil, garlic powder, smoked paprika, salt, and pepper. Spread them in a single layer on the baking sheet.
Bake the sweet potatoes for 15 minutes.
Remove the pan from the oven and add the salmon fillets and green beans. Drizzle the remaining tablespoon of olive oil over the salmon and beans, then season them with salt and pepper.
Return the pan to the oven and bake for 12 to 15 minutes more, until the salmon flakes easily with a fork and the sweet potatoes are tender.
Serve the meal with lemon wedges on the side.