Step 1Heat the oven to 350 degrees.
Step 2Heat 2 tablespoons olive oil in a Dutch oven over medium heat. Add the pancetta and cook, stirring frequently, until it begins to brown and render its fat, about 3 minutes. Add the onion and cook until soft, about 5 minutes. Add 3 cloves of minced garlic (about 2 tablespoons) and cook until fragrant, about 3 minutes.
Step 3Add the dried beans and water, cover tightly and bring to a simmer. When the water is simmering, stir and place in the oven. Bake for 1 hour before stirring in 1 teaspoon of salt. Cover again and return to the oven to cook, stirring occasionally, until the beans are tender, about 1 1/2 to 2 hours total.
Step 4Meanwhile, season the shrimp with the pimenton, ground cumin, the remaining 1 clove minced garlic and one-half teaspoon of salt. Heat a medium nonstick skillet over medium-high heat, add 1 tablespoon olive oil and, when it is very hot, add the shrimp. Cook, stirring constantly, until the shrimp are bright red on the outside and firm, about 3 minutes. Remove from heat and reserve.
Step 5When the beans are tender, stir the shrimp and the chopped dandelion greens into the stew. Cook just long enough to wilt the greens, about 5 minutes. Season to taste, adding first salt and then the sherry vinegar, adding it about one-fourth teaspoon at a time. It will take only about 1 teaspoon total. The stew shouldn't taste noticeably sour, just more complex.