I work nights on a small burn ICU that also takes off-service patients, and we don't have a tech at night. During the day, I assume the tech does normal 'tech' tasks such as blood-sugars, meal assistance, vitals (for pts who aren't on the monitor), helps with turns/bedding changes/cares/ambulation, transports non-monitored patients to procedures, peripheral blood draws if needed, etc. I think she also is supposed to help maintain the unit- stock rooms, answer the phone, etc. Our hospital uses techs to sit with confused patients, though, so she gets floated off our unit to sit on other units a lot. I don't know that it's much different from being a tech in any other ICU. She can help with dressing changes, but the RN is the primary person during a dressing change and must administer all the meds.
If you've never seen a big burn patient before, it's something people have trouble getting used to: the smell, the sloughing skin, etc... you'll have to judge for yourself what you're comfortable with.