Answer: Your question is a bit peculiar. After all, if one truly wants to commit suicide, there are not that many decisions to make after that. At a minimum, one could let nature take its course. But perhaps you are wondering about choices regarding how to commit suicide, and how to hurt one’s loved ones as little as possible, which might be issues that ethics should address. That is how I understand your question.
holds that life is the ultimate value. In nature, all values derive from the self-generated and self-sustaining actions of living things. Moral values derive from one’s choice to embrace life and happiness, rather than suffering and death. In this context, morality is not merely a guide for action, it is a guide for living.
What would it mean for an Objectivist to say that suicide was justified? After all, death is the zero. It is non-being. So it is not a state one can seek to live in nor a value to be attained. Suicide could be "justified" only in this sense: that one faced not a choice between life and death, but between death and death-with-suffering. Think of, perhaps, a person in the very late stages of a painful, mind-destroying, terminal illness.?But ethics as such can offer no counsel here: ethics, again, is a guide for living.
It is true that one needs relevant principles in order to succeed in reaching any goal whatsoever. And any goal can provide the anchor for a train of hypothetical norms, of the form "In order to gain/keep/do X, I must do Y." And it is true that if one has a goal, reason can discover the most effective ways of achieving that goal, even if that goal involves aiming for a certain kind of death, as in suicide.
Virtues like rationality identify principles of action. And actions can take a form consistent with those principles—or at least, some of those principles—even if they aren’t grounded in the right ethical base. People commonly identify a person of integrity, for example, as someone who holds to his principles, regardless of what those principles are. The Objectivist virtues are based in practical considerations; for Objectivism, moral action is practical, after all. But this means that there are practical reasons for acting in virtuous patterns, reasons that do not directly depend on what is the value being sought. This is true of integrity (as we just noted), objectivity (because you can’t act for a goal without knowledge of it), or even a basic element of justice (objectivity applied to judging people).
So we can see how a steadfast Roman who opens his veins to avoid dishonor seems virtuous, even though his action is disconnected from valuing his life above all else. And we can compare a methodical, resolute suicide with a panicked, desperate one. The aspects of ethics that help us be steadfast and methodical certainly apply to the goal of seeking one’s own death.
But when elements of virtue are taken out of their context, the effect is more often terrifying. The methodical and resolute Nazis murdered millions with great efficiency. In parts of the Muslim world today, a generation is being directed toward steadfast holy war and self-immolation. The death premise, accepted in itself, is tragic for the person who chooses it and for those who love him. But the death premise, allied to principles of objective knowledge and practical action, is extremely dangerous to all who seek life.
So the Objectivist ethics does not and cannot provide guidance for a suicide. But its practical basis does and can guide any range of practical actions to their appointed ends, including suicide. But that’s not usually a good thing.