I think it should be 2/3 tsp or 2/3 tbl sugar - not 2/3 of a cup of sugar :)
There are many strawberry and spinach salads recipes, but it is the dressing makes the salad. I felt this one was a bit too sweet for me, although my son and husband liked it, they are the sweet...
I make a very similar salad (dressing) and the ratio is 1/2 cup sugar to 1 cup oil. It's a delicious salad that everyone loves.