There are a great many ways to deal with radiation and flares, so starting in order of difficulty:
- Distance. Any spacefaring civilization can settle any body in free space or in orbit, so settling in cometary bodies in the star's Oort cloud puts you at sufficient distance from the star that flares become a minor annoyance. The ices of comets should contain sufficient Deuterium to run fusion reactors for thousands of years, and gigantic mirrors to concentrate solar energy can also be erected nearby, although the focal point should never be pointed at the colony.
To be totally realistic, the star would be so far away it would simply be the brightest star in the sky and not show a visible disc
- Digging in. If the colonists are closer to the star, they can simply burrow into the body in question until there is sufficient mass between them and the star to provide protection. On an asteroid, they could take the additional step of aligning the long axis to point at the star and burrow into the "dark" pole to put the maximum amount of mass between them and the star. Solar mirrors and energy collection devices can be placed on the "hot" pole facing the star. This strategy works for moons and planets orbiting close to the star as well.
An artificial cavern would look the same almost anywhere
- Artificial magnetic fields. With sufficient energy, artificial magnetospheres can be erected on or near planets, moons, asteroids or even artificial bodies in free space. While the L1 point may not be convenient with the star so close to the planet (typical planets orbiting Red Dwarf stars are found inside where Mercury orbits the Sun, for example), the magnetic device could be maintained in position using solar sails or other technology.
Keeping the magnetic field generator in place will be an issue
- Modifying the star itself. Star Lifting technology can be used to remove material from the star, but since it operates by modifying and applying magnetic fields around the star, it could potentially be used to control the magnetic fields around the star itself, or direct flares away from the planet to regions beneficial to the star lifting civilization.
Star lifting used to pump plasmas out of the stellar pole regions. This could also be used to redirect flares