Put oil in a large skillet over medium-high heat; add garlic and chili flakes and cook for about 1 minute. Add beans, wine, pasta and mussels; reduce heat to medium-low and stir to combine. Add as much reserved mussel liquid as mixture can accommodate without becoming too soupy. Cook, stirring gently, until pasta is fully cooked and everything is warmed through; add more liquid if you like. Adjust seasoning as needed, drizzle with a bit more olive oil if you like, sprinkle with parsley and serve.