For key visual step-by-step photos, refer to the body of the post.

Oven-dry the kirimochi:

• Use a sharp knife to cut the kirimochi into small tiny pieces, about ½ cm across. (If you prefer larger pieces, you can cut them bigger, but keep them under 1 cm as they will expand during the drying and frying process).
• Spread out the small pieces of kirimochi onto a baking tray.
• Dry in the oven at 250°F/121°C for 1 hour.
• Reduce oven temperature to 200°F/93°C and dry for one more hour. (Keep an eye on them to see if they're puffing and/or sticking together).
• Remove from oven and let cool completely.

The next day, or when ready to fry the kirimochi:

• Preheat oven to the lowest temperature, about 200°F/93°C.
• Place the kirimochi pieces onto a baking tray into the oven to warm up, about 15 minutes.
• Heat a small pot of high smoke-point vegetable oil over high heat.
• Once the oil hits a temperature of 425°F/218°C, place a few kirimochi pieces into the oil and quickly agitate with a pair of chopsticks.
• Fry until the mochi puffs up and floats.
• Remove with a slotted spoon and drain on paper towel.
• Season immediately with sea salt and/or furikake (seaweed seasoning).
• Repeat frying in batches.
• Cool completely before storing in an airtight container.