In general, there are a great many things you can serve as a side dish for quiche. For breakfast and brunch I favour bacon, sausage and fresh fruit. This can be whatever is in season from slices of orange or apple, ripe berries, wedges of watermelon or canteloupe, rings of pineapple or a handful of grapes.
For lunch or dinner then soups or salads are the way to go. Your salad can be anything from the green leafy variety to a carrot salad, cole slaw, beet salad or even a pasta salad if you have made a crustless quiche.
This particular quiche is rich in flavour and, keeping with the Mediterranean theme, well-suited to be paired with a Greek salad. Chop red and green bell peppers, red onion and cucumbers into rustic chunks. Add sliced olives and sprinkle with feta cheese and cracked pepper. For the dressing, combine 2 tbsp of extra virgin olive oil and 2 tsp of apple cider vinegar per person. Whisk together and pour over the salad.
If you don't want to serve a salad, then a cream of tomato soup would be a good option to pick up on the subtle flavour of the sundried tomato. In warmer weather another option would be gazpacho. I personally recommend Ina Garten's Gazpacho, a five star recipe that you can whip up in 20 minutes.
If you decide to make this a crustless quiche, then another great side option would be fresh baguette with olive tapenade.