Combine the Great Northern beans, 1/4 cup chopped onion, Parmesan cheese, 1/4 teaspoon salt, 1/4 teaspoon pepper, and 1 garlic clove in a food processor; process until smooth. Spoon white bean mixture into a bowl on one side; set aside.

Combine the black beans, 1/4 cup chopped onion, 1/4 teaspoon salt, 1/4 teaspoon pepper, 1 garlic clove, chiles, and cumin in a food processor; process until smooth. Spoon black bean mixture into other side of bowl containing white bean mixture.

Sprinkle cheddar cheese and green onions between 2 bean dips. Serve with Garlic Pita Chips.