Puree the peppers until very smooth along with the salt, pepper, vinegar, sugar, oregano and garlic.
The recipe does not call for any oil but you can add a few tbsp of extra virgin olive oil if you choose instead of the reserved pasta water.
During the summer months when fresh peppers are more plentiful and less expensive, I like to roast the peppers on the grill, getting them almost black before popping them into a Ziploc bag to sweat it out for 5-10 minutes. The charred skins are then very easily removed and discarded leaving the roasted flavor behind. I have also used good quality bottled roasted red peppers at other times of the year which is very good too.