In a small bowl using the back of a fork, smash the chickpeas so that some are partially smashed and some are left whole.
Add all the ingredients and mix together. Finish with toasted pine nuts and serve alongside the sumac sardines.
Pre-heat the grill to high, lay the prepared sardines with skin side-up in a single layer on a lined baking tray. Mix together the parsley, coriander, zest and juice of the lemon, sumac, garlic, Greek yogurt and salt in a bowl then spoon this mixture evenly over the sardines, making sure they are all covered.
Grill for about 5 minutes or until the sardines are completely cooked through and the skin is blistered.
Serve immediately with smashed chickpea salsa.