Shells with Gazpacho Sauce and Avocado

2 cloves garlic , smashed

1 jalapeño pepper , seeds and ribs removed

1/2 large red bell pepper , seeded

1 cucumber , peeled and seeded

1 pound plum tomatoes (about 5), seeded

1 3/4 teaspoons salt

1/2 teaspoon fresh-ground black pepper

1/4 teaspoon ground cumin

1/4 teaspoon wine vinegar

1/4 cup dried breadcrumb s

1/4 cup olive oil

2 tablespoons chopped fresh dill

1 avocado

3/4 pound medium pasta shells