Which Rasha is discussed?
Rashi: Amalek.
Radak: Resha'im that distract me from constantly engaging in Your wonders and deeds.
Malbim: Resha'im that succeed [in this world].
Why does he mention killing the Rasha?
Radak: Then, all my thoughts and engagement will be in You.
Malbim: Then, I will be able to answer all these questions about Hashem's knowledge. It says in Moreh ha'Nevuchim that philosophers came to these questions due to the evil order that appears in conduct - Tzadik v'Ra Lo, Rasha v'Tov Lo. Via this, they began to deny Hashgachah, for one cannot attribute to Hashem injustice. Via this they came to all their probing questions; they made them to establish and strengthen their reasoning.
What is the meaning of "v'Anshei Damim Suru Meni"?
Radak: I tell the Resha'im to go away from me [but I cannot enforce this].
Malbim: Resha'im will cease to ambush a Tzadik's Nefesh - there will not be found a Tzadik who suffers.