No plant likes to be watered with salty water, especially in a pot, the salt will concentrate in the potting medium. That said, Euonymus is listed as a salt tolerant plant (though that really means tolerant of salt spray near the coast rather than being watered with salty water).

The height and spread of any plant will be restricted if its in a pot - Euonymus is a fairly large group of plants and ultimate height and spread in the ground differs between 3 inches high and up to 15 feet. Select a variety appropriate for what you want - check out Euonymus fortunei varieties (smaller, evergreen) E. japonica varieties (taller, evergreen) and the deciduous ones such as E. alatus and E. europaeus. Note also that many are happier in part shade, and some do well with only a couple of hours sun a day.

We deal with our salty water by making sure that every watering is sufficient to drain some out the pot's drainage hole, and never letting them sit in drained water in a saucer. That way, the salt in the water never builds up in the soil to the point of poisoning your plants. I don't honestly know how our water compares to yours, Lim.