Can the sorcerer's Empowered Spell metamagic option be used to reroll the healing dice for the cure wounds spell (or, for that matter, any healing spell)?
Empowered Spell specifically states:
When you roll damage for a spell...
Healing is not damage so empowering spell doesn't apply to healing spells.
The divine soul sorcerer's 6th-level Empowered Healing feature from Xanathar's Guide to Everything, however, does allow you to reroll healing dice. As covered on page 50:
Whenever you or an ally within 5 feet of you rolls dice to determine the number of hit points a spell restores, you can spend 1 sorcery point to reroll any number of those dice once, provided you aren't incapacitated.