Cook the whole wheat penne pasta according to package instructions until al dente. Drain and set aside, reserving 1/2 cup of the pasta water.

In a large skillet, heat the olive oil over medium heat. Season the salmon fillets with Cajun seasoning, salt, and pepper. Place the salmon in the skillet and cook for about 4-5 minutes on each side, or until cooked through and flaky. Remove the salmon from the skillet and set aside.

In the same skillet, add the cherry tomatoes and spinach. Sauté for about 2-3 minutes until the spinach wilts and the tomatoes soften.

Reduce the heat to low and stir in the heavy cream and Parmesan cheese. Mix well until the cheese is melted and the sauce is creamy. If the sauce is too thick, add some reserved pasta water to reach desired consistency.

Flake the cooked salmon into bite-sized pieces and add it to the skillet along with the cooked penne pasta. Toss everything together until well combined.

Serve immediately, garnished with fresh parsley.