First, slice and soak the onions. Slice in rings, and place in a bowl covered with ice-cold water.
Prepare 2 baking sheets with parchment paper and preheat oven to 450 degrees. Let soak for 1/2 hour. Drain and pat dry with paper towels.
Place the chickpea flour with the sea salt in a ziploc bag.
Put the chickpea brine in a bowl.
Finally, combine the breadcrumbs, sea salt, and paprika in a third bowl.
Once mixing through, transfer roughly half of this mixture to another bowl.
(The onion rings will be coated in three steps - first in the chickpea flour, then the chickpea brine, and finally the breadcrumbs. Separating the breadcrumbs into two batches will help keep them dry so they will adhere to the onion rings. So, work with one bowl of breadcrumbs and then about halfway through the coating process, move on to that second bowl of breadcrumbs.)
Place the soaked/dry onions in the ziploc bag, seal, and shake to coat the rings.
Remove, and dip each ring in the chickpea brine (discard any remaining), and next into the breadcrumb mixture.
Place rings on the baking sheets. Bake for 15 minutes.
After that time, rotate the trays (from bottom to top), flip the rings, and bake another 10-15 minutes until golden and crispy! Serve.