30 minutes is doable but tight. Any delay in SFO will ruin your trip. Most SFO flights (RJ's) arrive at the E gates, NRT flight departs from a D gate (Usually D2 because it has access to DHS/Customs for arriving passengers). The D concourse is just around the corner and upstairs from the E gates, so, under normal conditions, it can be done in 10-12 minutes, but you wouldn't know the conditions until your SFO-SLC flight takes off.