The tsunami thesis has been conclusively disproven for decades, now, at the very least since Spyridon Marinatos' excavations of Akrotiri. To make a long story short, Akrotiri is a Minoan settlement on the island of Thera, and so it provides a rather airtight chronological relationship of Minoan culture vis a vis the eruption, because of course the eruption buried it. But we can see that the Minoan civilization chugged along quite well and was only "conquered" by the Mycenaeans several centuries later.

This actually makes a lot more sense than the old "catastrophe" model. If you think of it, there have been many, many horrific natural catastrophes throughout history, yet none of them led to the collapse of a strong state. The 365 Alexandria Tsunami did not lead to the fall of Rome, the 1755 Lisbon Earthquake did not lead to the collapse of Portugal, and as far as I can tell the United States did not cease to exist after Katrina. One group conquering another group though? That happens a lot.

As for where they came from, Linear A (the Minoan written script) has not been deciphered, so it is all a bit of a guess. The best guess as of now is that they developed as part of the complex world of interaction in the early/mid Bronze Age Aegean. In other words, they were indigenous, which sort of leads to a bit of a pedantic point: the Minoans did not come from or go anywhere, "Minoan" is an early twentieth century term designating a particular association of archaeologically recovered material that probably corresponds to some sort of socio-political formation that emerged on Crete some time in the early-mid second millennium BCE. There are no human beings who have ever thought of themselves or considered themselves to be Minoan.

Crete was first permanently settled in the early Neolithic (7th millennium BC) by people from Anatolia. The first known site of settlement on Crete was Knossos.^1

As to when the "Minoans" first existed, it really depends, but the term is most commonly associated with the "palaces" of the Protopalatial (c.2000-1750 BC) and Neopalatial (c.1750-1500 BC) periods.

As others have said, the "Minoan" language is undeciphered, making links to other places difficult. The tsunami theory is also a problem, at least in its basic form, as there appears to be a gap of 50-100 years between the eruption of Thera and large-scale cultural changes on Crete.^2 The most significant change is the replacement of the unknown language written in Linear A by the early form of Greek written in Linear B. While this has often been explained as a "Mycenaean invasion", it is now known that cultural features such as burials with weapons on Crete pre-date the Thera eruption,^3 and that the people buried with those weapons came from Crete, not elsewhere in the Aegean.^4 Whatever happened, it was clearly a complex process. Even after the "Mycenaeanisation" of Crete, the island still had a distinctive culture, and many aspects of "Minoan" culture spread to other parts of the Aegean and continued.

In terms of books, Preziosi and Hitchcock's Aegean Art and Architecture (1999) is a good place to start. If you want to go further, try out the relevant chapters of Cline (ed.) The Oxford Handbook of the Bronze Age Aegean (2012), which is a book I have set for starting undergraduate students.

References

^1 Watrous (1994) "Review of Aegean Prehistory III: Crete from Earliest Prehistory through the Protopalatial Period". American Journal of Archaeology 98.

^2 Manning and Sewell (2002) "Volcanoes and History: A Significant Relationship? The Case of Santorini", in Natural Disasters and Cultural Change.

^3 Dimopoulou (1999) "The Neopalatial Cemetery of the Knossian Harbour-Town at Poros: Mortuary behaviour and social ranking" in Eliten in der Bronzezeit: Ergebnisse zweier Kolloquien in Mainz und Athen.

^4 Nafplioti (2008) "‘Mycenaean’ political domination of Knossos following the Late Minoan IB destructions on Crete: negative evidence from strontium isotope ratio analysis (^87 Sr/^86 Sr)". Journal of Archaeological Science 35.