Farro Salad with Roasted Sweet Potatoes, Red Onion, and Goat Cheese

1 large sweet potato unpeeled and sliced into 1/2-inch-thick (12-mm-thick) rounds, large rounds halved
1 red onion cut into 1/2-inch (12-mm) wedges
4 tablespoons 60 ml extra-virgin olive oil, divided, plus more as needed for serving
Salt and freshly cracked pepper
3/4 cup 150 g dried farro
2 tablespoons red wine vinegar
3 radishes thinly sliced on a mandoline
1 small handful fresh dill roughly chopped
2 tablespoons salted pistachios roasted and roughly chopped
2 to 3 ounces 55 to 85 g goat cheese, broken into bite-size pieces
1/2 lemon juiced
Pinch smoked paprika for serving
Flaky sea salt
for serving

Preheat the oven to 425°F (220°C).
Spread the sweet potato rounds and onion wedges on a baking sheet, drizzle with 3 tablespoons of the oil, and season with salt and pepper. Roast, shaking the baking sheet halfway through, until the sweet potatoes are golden brown and tender, 15 to 20 minutes. Let cool slightly.
Cook the farro according to the package directions. Drain.
In a medium bowl, season the warm farro with the vinegar, remaining 1 tablespoon oil, salt, and pepper. Add the sweet potato, onion, radish, dill, pistachios, and goat cheese. To finish, drizzle the salad with the lemon juice and sprinkle with smoked paprika, flaky sea salt, and pepper. If the dish seems a little dry, drizzle it with extra oil.