I believe the vav of vayikra is a vav hamehapeich, meaning it switches yikra from asid to avar. To that extent I heard that the correct translation would be He called, rather than "and He called" (unlike [chabad translation])1. If so, why does targum translate ukra? which would indicate vav hamoseif?
The וַ (plus the dagesh in the yodh) is called "waw consecutive". At one time it was thought that this converted the verb from future to past, and the waw was called "waw conversive". We now know that the yiqtol form of a verb does not always indicate future and the qatal form does not always indicate past.
In prose, the wayyiqtol form is usually used to continue a narrative that was begun with a regular qatal form. In this case, the qatal and the following wayyiqtol generally do refer to the past. (Probably, the wayyiqtol form is a fossilized form that was originally a preterite form, as in Akkadian. The difference between the preterite and imperfect yiqtol was lost when short final vowels were lost in Hebrew.)
Since waw consecutive is not the same as waw conjunctive, it does not necessarily mean "and". (None of this was known to author of the Targum.) However, it's not possible to use both a waw conjunctive and a waw consecutive on one word, so whether the writer intends "and" or not, the form will still be wayyiqtol. In a narrative, a conjunctive often makes sense ("this happened and then this happened and then...) so translators have to make choices. Most (but not all) modern translators avoid using "and" so often that it sounds annoyingly repetitive. Robert Alter, however, believes that the writers intentionally used the repetition of waw to put a rhythm into the text, and therefore he does translate "... and ... and ... and ...". In the particular case of Wayyiqra, however, there may be a literary issue to be considered. Since, as I mentioned, the wayyiqtol form is the continuation of a narrative, it may be that it was intentionally used at the start of the book to emphasize its close connection to what came before (i.e., Exodus). Thus, some translators might use "And He called" to reflect this possible original intent.