Rub fish liberally with olive oil. Season with salt and pepper. Heat a large skillet over medium heat and lightly brown linguica. Add onion, garlic and fish. Lightly brown fish on both sides. Add pepper flakes, lemon juice, white wine and white beans. Cook for 2 minutes. Remove fish and arrange on warm plates. Increase heat to high, add basil and tomato and cook for 1 minute more. Spoon mixture on top of fish and top with cheese.