Put all the ingredients for arugula pesto in a food processor and mix it to make a smooth pesto. I kept a little chunky texture for the pesto as that's how we like it.
Place the bread on a baking sheet, drizzle with olive oil and broil it on high for 4 minutes.
In the meantime, heat a pan and cook the pancetta for about few seconds on each side to make it crispy.
Once the bread comes out of the oven, rub garlic on the hot bread.
Spread some pesto on the bread. Place 2 slices of mozzarella and two pieces of pancetta on top.
Sprinkle some chili flakes and enjoy!