Start by bringing a large pot of salted water to a boil. Once boiling, add the whole grain penne pasta. Cook according to the package instructions until al dente, which usually takes about 10-12 minutes. Drain the pasta and set it aside, reserving a cup of the pasta water for later use.
In a large skillet, heat the olive oil over medium heat. Add the crushed garlic and sauté for about 1 minute, or until fragrant. Be careful not to let it brown, as this can lead to bitterness.
Stir in the crushed red pepper flakes, allowing them to bloom in the oil for about 30 seconds. This step enhances the flavor profile of the dish.
Add the whole peeled tomatoes and fresh cherry tomatoes to the skillet. Stir well and let the mixture simmer for about 5-7 minutes, allowing the flavors to meld. If it looks too thick, add a splash of the reserved pasta water to achieve your desired consistency.
Drain and rinse the cannellini beans before adding them to the skillet. Stir gently to combine and let them heat through for about 3 minutes. Season with sea salt to taste.
Add the cooked penne pasta to the skillet, along with the baby arugula. Toss everything together over low heat until the arugula wilts slightly and everything is well combined. If needed, add more reserved pasta water to loosen the sauce.
Serve the Whole Grain Penne Pasta with Greens & Beans warm, garnished with additional crushed red pepper flakes or a drizzle of olive oil if desired. Enjoy this hearty dish on its own or alongside a fresh salad.