We have simulated the molecular dynamics of a KCl solution confined between two mica surfaces in equilibrium with a reservoir. For comparison, the simulations were also performed with pure water under the same conditions. The relation between normal pressure, lateral pressure in the solution layer, and quantity of water was first investigated. The position and orientation of the chemical species were then determined, showing the local molecular structure. Lastly, we simulated the mechanical response of the system submitted to a constant slip velocity for determining its frictional properties.