You should use rudder trim to remove any sideslip (keep the slip indicator centered). With the yaw damper on, this is taken care of automatically. Any remaining rolling tendencies can be fixed by either small amounts of aileron trim, or by use of the yoke. All aircraft have inherent rolling tendencies, especially those with a single nose-mounted engine. There will be slight differential fuel and payload weight between left and right, random air currents, engine torque and aileron trim effectiveness changes with airspeed, etc. Don't assume that you can take your hands off the controls and have the aircraft remain flying perfectly straight indefinitely. This is not the case in the simulator, nor is it the case IRL.