1. Cut out the stem of the tomato, then slice the tomato in half crosswise. Squeeze each half gently to extract the seeds and juices, discard them, and chop the tomato into ¼-inch dice.
2. Cut the avocado in half. With the tip of a small knife, loosen the seed and lift it out. Remove any brown tissue like fibers clinging to the flesh.
3. Strip off the skin with your fingers, starting at the narrow stem end (the dark-skinned variety does not peel easily; use a small, sharp knife to pull the skin away, if necessary). Chop the avocado into small dice.
4. In a large mixing bowl combine the oil, vinegar, chili paste (or fresh chili), salt and black pepper, and, with a large wooden spoon, mix well. Add the diced tomato, avocado, green pepper, chopped egg, parsley and coriander, and mix together gently but thoroughly.
5. Taste for seasoning. "Guasacaca" is traditionally served with grilled meats.
