Although trading went on, most food eaten was, by necessity, local. The port cities like Salem could import oranges, nuts, figs and more but for the outlying farms these items were exotic luxuries.
Salad (or salat) has been eaten for hundreds of years. Greens such as beet and turnip tops and spinach, cabbage are all greens that might be used. For the early New Englander, wild greens such as dandelion greens or violets would be eaten. (Fiddleheads are still eaten by Mainers, cooked of course, and have a flavor similar to spinach.) Our idea of a salad with lettuce and tomato was not the salad eaten by the early colonists. One of the memoirs from this time expressed a hunger for greens after a winter of salted and smoked food.
Poke weed was also used as a salad green. It is, however, poisonous, although the very young leaves – from accounts I have read – are not. I haven’t tried them. I have also read that the leaves are edible after cooking three or four times, discarding the water in between.
One note: since the native American tribes knew how to tap the sap from maple trees, maple syrup quickly became a staple. It was used as both lightly boiled sap, and the syrup we are more familiar with today.