Answer: 3 times.
1. In front of Piyush, Saanias case.
2. In front of Archie, when Kashish misunderstands that Sujal has removed Piyush's oxygen pipe.
3.When Kashish looses Piyush's child , she calls Sujal to come to that place where they used to meet and in dream she slaps him.
Now how many times did Sujal slapped Kashish ?