Cook the pasta according to package instructions in a large pot of salted boiling water until al dente. Drain and set aside, reserving ½ cup of the pasta water.
In a large skillet, heat the olive oil over medium heat. Add the minced garlic and sauté for about 1 minute until fragrant.
Add the cherry tomatoes to the skillet and cook for 3-4 minutes until they start to soften.
Stir in the flaked salmon and spinach, cooking until the spinach wilts, about 2 minutes.
Add the cooked pasta to the skillet along with the reserved pasta water, lemon juice, salt, pepper, and red pepper flakes (if using). Toss everything together until well combined and heated through.
Serve hot, topped with grated Parmesan cheese and fresh basil if desired.