Cut the cucumbers into rough chunks, place them in a blender and sprinkle with salt. Roughly chop the onion and add it to the blender along with the mint, green chilli, crushed cumin, yoghurt and water. Blend everything to a smooth, even consistency and season to taste with salt and pepper. Leave the soup to chill in the fridge for at least 1 hour so that it becomes thoroughly chilled and the flavours develop. Also place the deep plates for serving in the fridge.
Slice the spring onion into thin rings, roughly chop the coriander, finely dice the jalapeño and finely grate the garlic. Peel the cucumber and dice it into 1 x 1 cm cubes, then place everything in a bowl. Grate the lime zest and squeeze the juice into the bowl. Dice the avocados into small cubes. Add them to the bowl along with the olive oil, toss well and season with salt and pepper. Toast the bread slices on a griddle pan or in a toaster.
Finely chop the chives. Place three-quarters of the chives in a hand blender jug with the oil and blend until you have a green oil. Ladle the soup into the chilled bowls, drizzle or drop the chive oil over the soup, and sprinkle with the chopped chives. Divide the avocado salad between the warm bread rolls and, if desired, finish with a sprinkling of marigold and/or coriander flowers.
