Fry the bacon in the oven or pan until crispy. Cut into cubes and let cool off.
Wash the salad, spin dry and cut into bite-sized pieces. Wash tomatoes and cut into eighths. Cut the avocado in half lengthwise, remove the core, remove the flesh from the skin and dice finely.
Peel and finely chop the onion. Mix everything in a bowl with the lemon juice. Coarsely chop the walnuts and sprinkle over the salad.