Prepare the salad ingredients. Mix vinegar and room temperature water in a small bowl, soak the chopped onion in this mixture. Cut the cherry tomatoes in half, peel the sweet pepper and cut into half rings about 5 mm wide. Cut the avocado lengthwise, remove the pit and peel. Cut the fruit into medium slices 3-4 mm thick.
Make the salad. Combine the arugula, chopped vegetables, avocado and shrimp in a salad bowl. Drain the onion, squeeze the onion lightly with your fingers and add to the salad along with half of the cheese. Season the salad with salt and pepper, dress with olive oil and mix. Sprinkle pine nuts over the surface of the salad.