I don't know how to remove the sandstorm, but you might find this tip helpful for fighting in it:
Skip your first turn (don't move, don't do anything) and let the enemy come to you. You'll have nearly full AP and should be able to quickly kill one or two monsters. Make sure to focus your attacks on one at a time when possible to kill them quickly. If you have the ability to summon help, try to summon creatures with a ranged attack if possible, and then put them on the opposite side of the fight. And remember that most character builds should have ways to move considerable distances with a single attack (Rush, Lightning Strike, etc.)
It *is* a little harder in the sandstorm, you're absolutely right. But it's doable. Keep at it - you'll figure out the right strategy for your team.
