Preheat the oven to 425°F (220°C). Slice the bell peppers in half lengthwise and remove the seeds and membranes. Arrange them cut side up in a baking dish, drizzle with 1 to 2 tablespoons olive oil, and sprinkle lightly with about 1 half teaspoon salt total. Roast for 20 minutes, until the peppers are slightly softened but still holding their shape.
Boil farro in generously in salted water for about 10 to 12 minutes until tender but slightly chewy, then drain and set aside.
Brown ground beef in a large skillet over medium heat, breaking it up as it cooks, and carefully drain or blot away excess grease.
Add diced onion, salt, smoked paprika, and oregano to the beef and cook 3 to 5 minutes until the onion is soft and translucent.
Stir in minced garlic and cook 30 to 60 seconds just until fragrant.
Mix in crushed tomatoes, cooked farro, red wine vinegar, and balsamic vinegar and stir until evenly combined.
Fold in chopped arugula and goat cheese until lightly wilted and creamy, then remove from heat.
Spoon the filling evenly into the roasted pepper halves, pressing gently so they are nicely packed.
Top each pepper with your cheese of choice.
Bake at 425°F (220°C) for 15 to 20 minutes until the cheese is melted lightly golden and the peppers are tender.