Put the spinach, capsicum and red onion in a serving bowl.
Heat the oil in a large frying pan over a moderate heat. Add the bacon and cook for 5 minutes, or until crisp. Lift out with a slotted spoon to drain on paper towels. When cool, add it to the salad bowl.
Add the mushrooms to the pan and cook for 3–4 minutes until lightly coloured. Add the beans and stir-fry with the mushrooms to heat through.
Whisk together the vegetable or tomato juice, vinegar and mustard with salt and freshly ground black pepper to season. Pour into the pan with the bean and mushroom mixture and bring to the boil.
Immediately tip the hot vegetable mixture over the salad in the bowl and toss to combine. Serve warm.
Serve with pita bread or sesame pita bread. To make your own sesame pita bread, brush plain pita with a little oil, sprinkle with sesame seeds and warm under the grill until lightly toasted.