Bring a large pot of salted water to a boil. Add the spaghetti or linguine and cook according to package directions until al dente. Reserve 1 cup of pasta water before draining.
In a large skillet, heat the olive oil over medium heat. Add the sliced garlic and chopped chili, sautéing for 1-2 minutes until fragrant but not browned.
Pour the crushed cherry tomatoes into the skillet. Simmer for about 5-7 minutes until the sauce has thickened slightly. Season with salt and pepper to taste.
Add the drained pasta to the skillet with the tomato sauce, tossing to combine. If the sauce is too thick, add some reserved pasta water, a little at a time, until the desired consistency is reached.
Stir in the baby spinach and lemon zest, cooking for an additional 2-3 minutes until the spinach has wilted.
Plate the pasta and garnish with fresh basil leaves and a sprinkle of grated Parmesan cheese, if desired.