This recipe can easily be doubled or tripled and works very well as an appetizer. It tastes best when made a day ahead; cover and refrigerate the vegetables and cover the bread in a bowl to keep overnight.
Preheat oven to 350 degrees Fahrenheit. Spread sliced bread pieces flat on a large cookie sheet. Using 3 tablespoons of olive oil, brush a generous layer of oil on each slice of bread. Place cookie sheet in oven and toast bread for 20 minutes, checking occasionally to make sure bread doesn’t burn.
In a 3-quart mixing bowl, combine garlic, onions, watercress and tomatoes. Mix gently. Add vinegar and remaining oil. Mix until ingredients are fully coated. Add coriander, pepper and salt, mix gently. Adjust salt and pepper to taste.
When bread is toasted, remove from oven. Line a basket or bowl with paper towels. Place bread in basket and let cool.
When ready to serve, place toasted bread slices on a serving plate. Spoon a small amount of vegetables on each piece of bread. Garnish plate with lemon wedges or parsley.