I used to buy this all the time when I lived in portland and Trader Joe's carried tubs of it.  After a little trial and error, I came up with my own version.

Scratch Tomato Cucumber Tzatziki

(makes a big bowl to serve as dip for a party, or for two or three people as appetizer, or in my case, one lunch salad)

• one seedless cucumber (the shrink wrapped kind I best) partially peeled and sliced very thinly
• one small container of greek style plain yogurt (I used nonfat)
• about five campari tomatoes, sliced (it's not fully tomato season yet and these taste best) chopped
• salt
• a good palmful of dill
• small clove of garlic minced
• dash balsamic vinegar
• torn fresh mint leaves if you have it

Method:

Slice the cucumber as thin as possible, salt lightly, and drain in a colander lined with paper towels for a few minutes. If you skip this step, it's fine, but the yogurt will break down and get watery but it shouldn't affect the taste.  Add the tomatoes and cucumbers to a large bowl and salt lightly again. Toss with the garlic and the rest of the ingredients until the yogurt covers everything and season to taste. It should be cool and crunchy with a little sweetness from the tomato and tartness from the yogurt and vinegar.