I went to a small grocery store near Andrew's apartment that doesn't have the largest selection but it does the trick and it's a nice and small enough that you don't feel like you are being consumed by a regular sized grocery store.
The vegetables I used were basically what was available at the store: green beans, snow peas, broccoli, red pepper, and some water chestnuts.

Homemade Orange Sweet/Sour Sauce
Ingredients:
2 tsps. Spicy Chili Garlic Sauce (similar to the kinds they serve in restaurants)
2 in. Chunk of Fresh Ginger, peeled and to taste
2 Lemons (or bottled lemon juice will work)
2 Cups Orange Juice (I used with some pulp)
2 tsps. Cornstarch
8 tsps. Water

Directions:
1. Put a frying pan over medium heat. Add in hot chili garlic sauce and orange juice. Stir until mixed and beginning to boil.
2. Grate the fresh ginger into the pan (remember, to taste). Continue to lightly boil the sauce.
3. Mix the cornstarch in a small bowl with the water, until dissolved. Add mixture to the sauce.

4. Continue to stir and allow sauce to boil lightly as the sauce thickens up. When the sauce has thickened to your liking, squeeze in the fresh lemons and give the sauce one more stir.
5. Pour over veggies (and in this case, quinoa).

The sauce is citrus-y with a very pleasant kick. It would also work well on some pork chops with pineapple, onion and pepper or as a sauce on "orange chicken". I plan to use this basic recipe a lot in the future... small tweaks can greatly effect the sweetness, spiciness, or sourness taste!
Enjoy!