Great Mixed Raw Salad La Grande Insalata Mista

½ medium red onion, very thinly sliced
1 small carrot, peeled and sliced thinly into rounds
1 small fennel bulb, trimmed and sliced thinly on the diagonal
½ a red and yellow capsicum, seeded and cut into strips
1 celery heart, leaves removed and sliced into thin rings
1 small radicchio lettuce, torn into large pieces
heart of a soft green lettuce, washed well, dried and torn into large pieces
handful of rocket leaves
four preserved artichoke hearts, drained and quartered
2 firm but ripe tomatoes, roughly chopped
sea salt
extra virgin olive oil
red wine vinegar