Oranges are quite high in fruit sugars, raising your carbs per mouthful.
The wishbone dressing seems to be member entries, not the site database. They are all 7g of carbs per 2tbsp, not 2g. Perhaps you have a slightly different version or something? Or misread fat for carbs or something (it has 2g fat)? If you find that no entry has the same nutritional information as your bottle, you should make and use your own entry. That way you'll know it's accurate.
You're right that an orange and a pepper with some dressing is not a meal!
I don't like tuna, so I honestly don't know if this goes together well, but for example, how about:
120g tuna, half a cup of green bell pepper, a couple of handfuls of spinach, with balsamic vinaigrette dressing, and a cup of non-fat milk.
This is 316 calories and 22g of carbs.
Deb, in New Zealand