1 small red onion, very thinly sliced (about 1/2 cup/55g)
1/2 teaspoon flake sea salt
1/2 cup (20g) chopped fresh flat-leaf parsley
1 teaspoon ground sumac
In a colander or sieve, toss onion slices with salt and let stand for 5 minutes to soften and reduce the harshness. Rinse and drain well.
Transfer the onion to a bowl and toss with parsley and sumac. Serve within 30 minutes.