In processor, pulse beans, 2 tbsp. panko and next 8 ingredients to blend. Form into 8 balls. Coat veggie balls in egg white, then remaining panko. In medium nonstick skillet, heat EVOO over medium. Cook balls until browned all over, 8 to 10 minutes. Mix salsa and chopped cilantro. Build sliders with buns, balls, salsa, cilantro leaves and onion.