Preheat the broiler. Place the bread slices on a cookie sheet and brush with a little olive oil. Toast until golden brown. Slice one garlic clove in half and rub over the warm toast.
In a small-medium bowl, gently combine 1 tablespoon olive oil, the minced garlic, tomato, avocado, white balsamic, salt, basil, and cucumber. Season to taste with more salt and/or vinegar if desired.
Serve the avocado topping with the toasted bread. Topping will keep refrigerated in an airtight container for up to 24 hours.