Cook the penne according to the package directions. Meanwhile, heat the oil in a large saucepan over medium heat. Add the bell peppers, salt, and 1/4 teaspoon of the black pepper. Cover and cook for 4 minutes. Stir in the garlic and red pepper flakes and cook for 1 to 2 minutes. Add the pasta sauce and cook until heated through, about 3 minutes. Drain the pasta and divide it among individual bowls. Top with the sauce, a dollop of the ricotta, and the remaining black pepper.