Remove the chicken from the refrigerator one hour before you start cooking,coat liberally with oil and season with sea salt.
To make the romesco,preheat your oven grill. Put the tomatoes on a tray and cook under the grill for 5-8 minutes,until they dehydrate and start to colour. Place the olive oil in a pan and fry the chillies over medium-high heat,turning until blackened (about 30 seconds),then remove. Put the garlic and sea salt in a mortar and crush to a paste with the pestle. Add the fried chillies and crush,then add the nuts and pound until completely ground. Add the grilled tomato and the paprika and pound gently,then fold through the breadcrumbs and add the vinegar. Drizzle in the olive oil and check the seasoning,adding a generous amount of freshly ground pepper. (Makes about 325ml.)
Preheat barbecue to high. Brush the chicken with extra olive oil and place skin side down on the grill at a 45-degree angle to the bars. Halfway through cooking the first side,turn the chicken 45 degrees,creating a crisscross pattern. Turn the chicken over to finish cooking. The chicken will take 12 to 15 minutes,depending on the size. Remove from the grill,put on a plate,cover with foil and allow the bird to rest in a warm place for 10 minutes.
Drizzle a little extra olive oil into the juices on the resting plate and add the lemon juice,a grind of fresh pepper and the herbs. Mix together and spoon this dressing over the chicken. Serve immediately with the romesco.
If you like this,try Adam Liaw's romesco salad recipe.