Meanwhile, in food processor bowl with metal blade, place cilantro, parsley, basil, onions, garlic, lime juice, and the remaining 2 teaspoons oil and 1/4 teaspoon salt. Cover and process about 10 seconds or until finely chopped. With processor running, slowly pour in broth and continue processing until almost smooth. Stir in cheese. Serve 3 tablespoons pesto with each tuna steak.