Preheat the oven to 375 degrees . Rub the peppers with 2 tbsp. EVOO and season with salt and pepper. Arrange the peppers, cut side down, on a foil-lined baking sheet and bake 10 minutes. meanwhile, cook the quinoa according to package directions.
In a large skillet, heat the remaining 1 tbsp. EVOO over medium. Add the pork and garlic and cook, breaking up the pork, until cooked through, about 6 minutes. Stir in the cooked quinoa, tomato sauce and paprika; season.
Spoon the filling into the peppers and bake until the peppers are tender, about 20 minutes. Sprinkle with the feta.