For exemple - Cinccino with Skill Link Ability ,Tail Slap move and holding Choice Band. (Hit 5x)

What is the base power of 1 single hit(does it get boosted by STAB and Choice Band?) and what is the total base power of the move?

The base power of one hit is 56.25, after being boosted by Choice Band and STAB. Here's a calculation:

25 1.5 1.5 = 56.25

If the move hits 5 times, the power will be 281.25. Here's another calculation:

(25 1.5 1.5) * 5 = 281.25

Hope I helped!