Heat the olive oil in a large skillet over medium heat. When the oil is hot, add the pancetta and cook until it starts to crisp and turn golden.
Add the fennel, shallot and garlic, and sauté until the vegetables are tender and translucent, 3-4 minutes.
Add the beans and tomatoes to the skillet, stirring to combine. Cook until the beans are heated through and the tomatoes have started to burst. Remove from the heat and stir in the vinegar.
Pour the beans into a large serving bowl and top with baby spinach leaves. Toss together and season with salt and pepper to taste. Finish with a drizzle of peppery extra virgin olive oil. Serve warm or at room temperature.