Prepare pasta according to package instructions, reserving ½ cup of the starchy cooking liquid.
While the pasta is cooking, heat olive oil over medium-high heat in a deep skillet. Sprinkle shrimp with salt and pepper on both sides and add to pan in a single layer. Cook until shrimp is pink, about 3 minutes total, turning once.
Add garlic to the shrimp and sauté until fragrant, about 30 seconds, being careful not to burn. Stir in lemon juice, lemon zest and spinach/arugula blend. Sauté until greens start to wilt, about 2 minutes.
Stir cooked pasta, parmesan cheese and reserved cooking liquid into the pan and toss to coat. Season with chili flakes and additional salt and pepper to taste before serving hot.