Wash arbi thoroughly and then pressure-cook it. (This is how I cook it in pressure cooker: Heat some water in the cooker and then add a steel container with arbi in it. Close the lid of the cooker and cook on medium-high heat till one whistle. Turn off heat and allow pressure to settle.)
Allow the arbi to cool and then refrigerate for about an hour. (This is too prevent arbi from being sticky.)
After an hour take it out of the fridge, bring to room temperature and then peel. (Use a knife or a peeler to remove the first segment of skin. Then you can just remove the remaining with your hands.)
Cut into slices.
Heat oil in a kadai (deep pan/wok), and when the oil is hot, add arbi slices.
Turn the slices intermittently to ensure they get cooked properly from both sides.
Transfer the arbi chips onto a plate lined with paper towels, and then add in the next batch of arbi slices in the kadai for frying. (I had to fry arbi in 3 batches.)
Season with salt, red chili powder, and black pepper powder. (Red chili powder can be slightly more than black pepper powder, but the quantity depends on your preference.)