after i repaint my skateboard, should i spray lacquer over it to help it slide?

Answer 1

I would use a clear polyurethane as it's very durable. This comes in brushable liquid or in aeresol cans.
You can dust the wet clear coat with fine sand if you desire traction. They also make a sand like material specifically for this purpose...typically found at paint stores. Good Luck.

Answer 2

Clear laquer or Poly will seal the paint and help prevent damage to it. As for sliding, I would wax the surface afer it dries.