Thinly slice the fish and add to a bowl. Cover with lime juice and zest from 1 lime, then cover with salt. Top with ice cubes and place it in the fridge until needed.
Mix the olive oil, juice and zest from 1 lime. Place in the fridge to chill.
For the banana emulsion: In a blender mix the banana, juice and zest of 1 lemon, jalapeño, salt and pepper and slowly drizzle 2 Tbsp of lemon grass oil.
To Serve: Pour the lemon dressing over the fish mixture and immediately mix it up. Leave it to sit for about 1 minute. Plate the sea bass with some of the juice, add the green peppers, the avocado, the pickle red onion and the black sesame seed. Pour the banana emulsion around the ceviche.Serve immediately.