Roasted Eggplant and Pickled Beet Sandwiches

INGREDIENTS

• 4 scallions, thinly sliced
• 1 large eggplant (1 1/2 pounds), sliced into 1/2"-thick rounds
• 1 garlic clove, finely grated
• 1/4 cup chopped pitted oil-cured olives
• 1/4 teaspoon smoked paprika
• 1 tablespoon olive oil
• 6 ounces feta, thinly sliced or crumbled
• 1 cup mixed tender fresh herb leaves (such as flat-leaf parsley, dill, and mint), torn if large
• 1/2 cup mayonnaise
• 1/2 cup chopped pickled beets
• 4 6x4" pieces focaccia, split
• 2 tablespoons drained capers
• 2 teaspoons Sherry vinegar
• Kosher salt, ground pepper
• 1/4 cup olive oil