Using tongs, hold the pepper over a gas flame until black all over. Put it into a bowl, cover with cling film and leave for a few minutes. Remove the black skin from the pepper, scoop out the seeds and chop the flesh.
Now heat a pan to medium-hot. Rub the sourdough with half the oil and the garlic and grill on both sides until browned. Set aside.
In a bowl, mix the spring onions, parsley and chilli. Toss in the Piquillo peppers.
Preheat the grill to high. Spread the remaining oil on a baking tray. Add the sardines, season with salt and pepper and grill on one side for 1 minute, or until cooked.
For the slaw, place the vinegar, water and sugar in a saucepan and heat until the sugar has dissolved. Mix the other slaw ingredients in a large bowl. Just before serving pour over the liquid and add the coriander.
To serve, garnish on the bread with the pepper mix, add the sardines and finish with a touch more garnishes and a squeeze of lemon. Serve immediately with the slaw