Using a slicer, cut the oranges crosswise into rings.
On each of four chilled plates, arrange orange cross sections in a single layer, over lapping slightly, in the style of carpaccio. Season oranges with Maldon sea salt an fresh black pepper. Sprinkle each plate with about a tablespoon of the fresh mint chiffonade.
In a small bowl, combine the red onion rings, jalapeño, and gaeta olives. Season with salt, pepper, a squeeze of lemon juice and extra virgin olive oil. Distribute the olives, red onion and jalapeño evenly on the four plates.
Drizzle each plate with oil and finish with a generous grating of bottarga.