I don't know the exact recommended amount of torque but, Never over tighten. As a rule when tightening small screws, I screw them in until they are just tight and stop. No need to give it that "extra" turn or torque.
Small screws strip very easily. Better to have to re-tighten or use a bit of lock tight or Teflon tape then deal with a striped screw or worse a sheared off screw head.
Less is more, never over tighten.
Edit to add: Obviously if it's the pivot screw you tighten to your liking as it effects how tightly the blade is held. Generally I've almost never had to adjust it when it comes from the factory. I will always use the knife a while first. Let thing's break in and set or settle before I decide to make any adjustments. Even if you think it's a bit tight at first. Wait a while before you adjust anything. Gives it time to settle.
Hope this helps.