In a large pot of lightly salted boiling water, cook the penne according to package directions.
Drain the pasta and set aside.
Meanwhile, in a large skillet over medium-high heat, add the olive oil and garlic. Cook 30 seconds, stirring constantly, to release flavors.
Add the spinach, crushed red pepper, salt, pepper and water; cover, and cook, stirring occasionally, for 5 to seven minutes, until the spinach is defrosted and heated through.
Add the penne and diced tomatoes, stirring well to mix. Cook for 5 minutes, or until heated through and slightly thickened.
Remove from heat; add the Parmesan cheese; toss well to mix.