Smashed Potato Salad

• 1 kg potatoes
• 2 tbsp extra virgin olive oil
• 30 g parmesan cheese, grated
• 1 cucumber, finely diced
• 1 capsicum, finely diced
• 2 cup celery, finely chopped
• 1 red onion, finely diced
• 2 cup Greek yoghurt
• 2 garlic cloves, finely grated
• 0.25 cup capers
• 1 tbsp tahini
• 1 lemon, juiced
• 0.25 cup dill
• 1 tsp salt