Empty the cannellini beans into 2 separate bowls. Using a potato masher or a spoon, mash the beans in one of the bowls. Set aside.
*You may also purée the beans
Put a large skillet over a medium flame and heat the oil. Add the red pepper flakes and garlic and cook until they garlic is fragrant, about 30 seconds.
Drop the pasta into generously salted boiling water.
Add the tomatoes and salt. Cook until they begin to break down, about 5 minutes.
add the mashed and whole beans to the pan along with 1/2 cup of pasta water to loosen the mashed beans. Cook for an additional 5 minutes. If the Pan seems dry add another 1/2 cup of pasta cooking water.
Add the arugula to the pan and cook until just wilted.
Drain the pasta and add it to the pan. Toss over high heat for 1-2 minutes. Serve in warm bowls with an extra drizzle of extra virgin olive oil.