Green Goddess Tuna Salad Sandwich

Name: Green Goddess Tuna Salad Sandwich
Ingredients: 1/4 cup basil leaves; 1/4 cup parsley leaves with tender stems; 1/4 cup tarragon leaves; 1/4 cup mayonnaise; 1/4 cup sour cream; 1 tsp. finely grated lemon zest; 2 Tbsp. plus 1 tsp. fresh lemon juice; 2 Tbsp. extra-virgin olive oil, plus more for drizzling; 1 (5-oz.) can tuna in water, drained; 1 celery stalk, finely chopped; 1 small shallot, finely chopped; 1 garlic clove, finely grated; Kosher salt, freshly ground pepper; 1/2 cup coarsely chopped mixed tender herbs (such as celery leaves, basil, parsley, and/or dill); 2 English muffins, split, lightly toasted