Salt came into the game after a record-breaking 141 not out against South Africa and put Ireland's bowlers to the sword as England chased down a total of 197 with more than two overs to spare.
The opener struck 10 fours and four sixes in his knock and was the key contributor but received good support from Jos Buttler (28), Sam Curran (27) and stand-in captain Jacob Bethell (24).
The home side's bowlers were up against it against the hard-hitting English batters but Matthew Humphreys (2-44) and Graham Hume (2-36) put in a decent shift in the defeat.
Earlier, Ireland thought they had a good total on the scoreboard when they reached 197-3 in their 20 overs after being put in to bat at the toss.
Harry Tector top-scored with an unbeaten 61 from 36 balls while Lorcan Tucker hit 55, also off 36 deliveries.
The hosts were given a decent start when opening pair Paul Stirling (34) and Ross Adair (26) put on 57 inside eight overs before spinner Liam Dawson (1-39) made the breakthrough for England.
The second match is due to be played in Dublin on Friday with the series concluding at the same venue on Sunday.
England fast bowler Mark Wood says he wants to up his intensity as he builds up to put himself in the selection frame for the first Ashes Test that starts in Perth on 21 November.
Laura Wolvaardt played one of the all-time great ODI innings to guide the Proteas Women into the ICC Women's World Cup final after a comprehensive 125-run victory against England.
England fast bowling legend James Anderson has been knighted for his services to cricket.
New Zealand battled past England by four wickets at Bay Oval on Sunday in the first match of their three-game ODI series, with half-centuries from Daryl Mitchell and Michael Bracewell proving pivotal.
