There are ways to minimize the risk, but no way to just not fight. You can unequip your weapon before encountering them, to ensure you do less damage if you do hit. You can keep your distance where possible (especially from Animal intelligence monsters, as they won't generally approach if you don't get close). You can take steps to discourage them from chasing you like Confusing or Paralyzing them... that's about it, at present.
Might be a neat idea to add a toggleable "Pacifist" button or something where you can turn off your side of the fight, though. Never occurrred to me before. I'll look into it.