Heat the oil in a large saucepan, over medium heat. Add the pancetta and cook until crispy and golden, 8 to 10 minutes. Using a slotted spoon, remove the pancetta from the pan, place on a paper towel-lined plate, and reserve.
Increase the heat to medium-high and add the onions to the hot oil. Saute until soft, about 3 to 4 minutes. Season the onions with salt and pepper. Add the garlic, bay leaves and chiles, and cook for 5 minutes. Add the tomatoes and stock. Adjust the seasonings with salt and pepper. Bring the liquid to a boil and reduce to a simmer. Cook for 10 to 15 minutes or until the tomatoes soften.
Remove the bay leaves, and using a handheld blender, puree the soup until smooth. Alternatively, you can omit blending and leave the soup chunky. Stir in the lemon juice and hot sauce. Adjust seasonings with salt and pepper.
To serve, ladle the soup into individual bowls and garnish with a drizzle of Cilantro Oil and the reserved pancetta.
Bring a medium pot of water to a boil. Add the cilantro and blanch for 10 seconds. Remove and shock in an ice bath. Pat dry well on paper towels, squeezing to remove any excess water. Roughly chop and transfer to a blender. With the machine running, add the oil and salt and process until smooth. Transfer to a squirt bottle and refrigerate until needed, for up to 1 week. (Bring to room temperature before using.)
Yield: about 1/2 cup