It’s possible, yes. It’s not highly likely.
Coronal Mass Ejecta have caused many problems with the magnetosphere of the earth, caused massive EMP on electrical systems (taking down power systems and generators in hydro plants in the past). Causing fires is a bit more difficult, but a solar flare could conceivably hit us. CMEs throw out more matter, in general than a flare though.
All they are claiming is there is a correlation between forest fire outbreaks and solar activity. Whatever mechanism/indirect effects that is causing this correlation they don't speculate on.
As for thermal corpuscular energy, this study is from Portugal so there might be a translation problem.