I applied for B2 Tourist visa at Israel embassy in New Delhi last week. But my visa application got rejected and stamped a black stamp on my passport.
What does black stamp mean? After how much time should I reapply for tourist visa?
As @NeanDerThal correctly commented, this is not a rejection.
The stamp says, in Hebrew, "A visa request has been submitted. Place: New Delhi. Date: 2/11/17" (i.e. November 2nd 2017).
If this is why you think your application was rejected, you can relax - it was not rejected. I couldn't find reliable information about processing times, but it should take at least a week (one site says 14 business days).
I hope you enjoy your Christmas in Israel.
A visa request has been submitted on 2/11/2017 in New Delhi