Roughly chop the tomatoes, pepper and chilli and place in a bowl. Cut the avocado in half. Slice the flesh from both halves into chunks and add to the chopped ingredients. Pour over a generous amount of olive oil, season with salt and pepper and set aside.
Grill the calamari steaks for two minutes on each side, or longer if you don't want them too underdone. Season with salt and pepper on both sides and allow to rest in a warm oven.
To serve, divide the salsa equally on four plates, place the calamari steaks on top; sprinkle with the chives and coriander and serve with half a lemon or lime.