Preheat oven to 350°. Place pita bread on baking sheet and brush with olive oil. Sprinkle with oregano, salt and pepper, and bake until crispy and golden, about 10 minutes. Cool and break into pieces.
Drain beans and set aside liquid. In food processor, combine drained beans and remaining ingredients. Process until smooth; for smoother texture, add reserved liquid. Serve with pita crisps.