Cook pasta in a large pot of boiling salted water according to package directions for al dente. Drain well.
Meanwhile, heat oil in a large, high-sided skillet over medium. Add garlic and crushed red pepper; cook, stirring occasionally, until fragrant, about 1 minute. Add wine and lemon slices; bring to a gentle simmer over medium. Add mussels; cover and cook, undisturbed, until mussels open, about 5 minutes. Remove from heat. Transfer mussels to a large bowl using a slotted spoon, discarding any mussels that did not open; reserve broth in skillet. If desired, remove mussel meat from shells, and place in a small bowl; discard shells if not using.
Return broth in skillet to a simmer over medium. Add drained pasta and mussels. Cook, stirring and tossing, until sauce thickens slightly and pasta is well coated, about 2 minutes. Remove from heat. Add chopped mint, salt, and black pepper; toss until well combined. Season with additional salt and black pepper to taste. Garnish with mint, and serve.
