According to Catholicism, how should Christians react when an unbeliever dies? I was reading the following passages, and they seem to indicate that we should rejoice when God brings about His judgement:

&quot;Righteous art thou, O YHVH, and upright are thy judgments.&quot; Psalm 119:137

Also:

&quot;But, O YHVH of hosts, that judgest righteously, that triest the reins and the heart, let me see thy vengeance on them: for unto thee have I revealed my cause.&quot; Jerimiah 11:20

And:

&quot;Then shall the trees of the wood sing out at the presence of YHVH, because he cometh to judge the earth.
O give thanks unto YHVH; for he is good; for his mercy endureth for ever.&quot; 1 Chronicles 16:33-34

One more:

&quot;But let him that glorieth glory in this, that he understandeth and knoweth me, that I am YHVH which exercise lovingkindness, judgment, and righteousness, in the earth: for in these things I delight, saith YHVH.&quot; Jeremiah 9:24

I'm seeing several, maybe even hundreds, of verses that confirm God's judgment is righteous and good. Unless I'm missing something, God's judgement seems to be something Christians should be excited and happy about.
So according to Catholicism, should Christians (of any sort) rejoice when an unbeliever (specifically those that have outright denied Christianity: ex. Atheist, Muslims, Hindu) dies and God subjects their flesh to be burned for eternity?
According the Catechism of the Catholic Church


  Since Christ died for all, and since all men are in fact called to one
  and the same destiny, which is divine, we must hold that the Holy
  Spirit offers to all the possibility of being made partakers, in a way
  known to God, of the Paschal mystery." Every man who is ignorant of
  the Gospel of Christ and of his Church, but seeks the truth and does
  the will of God in accordance with his understanding of it, can be
  saved. It may be supposed that such persons would have desired Baptism
  explicitly if they had known its necessity.


So, I'd say first of all that your question made be based on a false premise. But taking just the words of your question at face value, I'd refer you to 1 Timothy 2-4; Ezekiel 18:23, 32 and probably many other verses.

I'd also suggest that the proper response is no different from the proper response in an earthly context. When some malefactor receives proper justice at the hands of the courts, should we rejoice in their misfortune? Of course not. But we can be glad that their unlawful and predatory behavior will no longer continue, and hope that others who may be tempted toward such behavior may be dissuaded by the example of their punishment.

As to hell being a place of physical torture, again I'd have to say that your question is based on a false premise. The church teaches that, 


  "The chief punishment of hell is eternal separation from God, in whom
  alone man can possess the life and happiness for which he was created
  and for which he longs."


So from the perspective of the saved, basking in the splendor and glory of the beatific vision, such separation is torture, and so those metaphors are appropriate. 

For me, the most cogent depiction of hell can be found in CS Lewis' "The Great Divorce". It answers the question I think you're getting at: "How can a loving and good God create clay-footed creatures whom he then condemns to an eternity of torture while they beg and plead for forgiveness and mercy". (Hint: He doesn't) Although Lewis was not Catholic, I see nothing in what he relates there that is inconsistent with the church's teaching. I recommend it most highly, especially if this question poses difficulties for you. It's an easy, fun read, to boot.