Using a scrubber, scrub all the mud off the arbi / colocassia under running water.
To pressure cook the arbi, place the arbis in a cooker vessel with a little water (1/2 cup or so), more water in the cooker, after two whistles, place on sim for 5 minutes. This should do to cook medium sized arbis without turning them to mush, in which case, you really cannot progress further.
One the cooker has cooled, open, and remove the arbi to a plate and cool for 10 minutes till comfortable to peel.
Once peeled, place them in a single layer in a large dish. With your palms or a wooden masher, lightly flatten each piece until oval / round, but not with so much force that it crumbles.
With a gentle hand, coat the spices over the arbi and let this sit for 15 minutes minimum. You could also refrigerate the dish covered with cling wrap until the time you want to shallow fry and serve.
In a cast iron or any suitable skillet, heat 2 tbsp of vegetable oil. Place the well marinated arbi pieces in a single layer. Let these acquire a golden brown crust on one side (takes around 7-10 minutes) after which turn them over and crisp up for 10 more minutes.
Serve hot with green chutney or a date tamarind chutney. We had it with store bought Date Tamarind Chutney (Kitchens of India, ITC) and it went superbly along with some slices of cool cucumber.