Is salty tongue effect normal after eating sichuan peppercorns?
Yes. This happens to me. Some scientists are investigating the possibility of using the peppercorns as a means of reducing people's salt intake.

Potential of Szechuan pepper as a saltiness enhancer, Tram Hong Le Bao, Siree Chaiseri and Yaowapa Lorjaroenphon, International Journal of Food Properties 21(1), pp533-545.