Make the dip: In a small skillet over medium heat, heat 1 tablespoon of the oil until shimmering. Add the onion and cook, stirring occasionally, until softened, about 3 minutes. Stir in the garlic and cook until aromatic, about 30 seconds. Stir in the chili powder, cumin and coriander and remove from the heat. Let cool slightly, about 10 minutes. In the small bowl of a food processor or a mini-chopper, combine the beans, lime juice, water, salt and pepper, and the remaining oil. Add the onion mixture and process until smooth. Add the cayenne pepper and additional salt, if desired. You should have about 1 1/2 cups of dip; you will need a heaping 1/3 cup for the lunchbox. Refrigerate the remaining dip until needed for another lunchbox or use. Make the lunchbox: Place 1/3 cup of the dip in one section of a divided container or into a separate small, lidded container. Sprinkle the top with the cheese. Fill the rest of the divided container with the peppers, carrots, celery or jicama, or pack them in a separate container. Pack the chips in a separate small bag so they keep their crunch. To eat, dip the vegetables and chips in the black bean dip.