In Greek, when you talk about the ingredients in a dish but you don't specify the quantity used, you use the singular. For example, the plural of this sentence would be: "Οι πίτσες έχουν τυρί και ντομάτα".
Both τομάτα και ντομάτα are correct. "ντομάτα" is in fact more common. Please try not to use a mass of question marks we are quite ready and willing to reply to your every question without these mulitiple emphatic symbols.