  Although more than 5000 TESS Objects of Interest have been cataloged, no
comprehensive survey of the flare rates of their host stars exists. We perform
the first flare survey of all 2250 non-retired TOIs with 2 min cadence light
curves to measure or place upper limits on their flare rates. We find 93
candidates orbit flare stars and measure their flare frequency distributions.
Across the sample, TOIs of <1.5R_Earth orbit flare stars more frequently than
do TOIs of 1.5<R<2.75R_Earth, 2.75<R<4R_Earth, or R<4R_Earth. We sort all TOI
host stars by their flare rate/upper limit, stellar mass, and distance to
create a flare ranking metric (FRM) to determine suitability for follow-up. The
FRM of each TOI is then checked against the expected signal-to-noise of
atmospheric features in transmission spectroscopy to locate the most promising
targets. We find 1/4 of terrestrial M-dwarf planets amenable to transmission
spectroscopy orbit flare stars. However, none of the M-dwarf hosts to
terrestrial planets are currently flaring at sufficient levels for >99.9%
atmospheric ozone depletion. We give the first upper limits on the flare rate
of the host star to TOI 700 d and explore the flare rates incident on young
planets such as DS Tuc Ab.
