Preheat oven to 4oo degrees. Slice mini bell peppers in half and remove stem and seeds. Place in a large bowl (or large ziplock bag) and toss with pesto, olive oil and balsamic vinegar until peppers are completely covered. Line up peppers on a baking sheet and place into oven. Bake for 15 minutes. Take peppers out and carefully add crumbled goat cheese to insides of pepper halves. Place back into oven and bake for another 3-5 minutes or until goat cheese is melted. Optional: sprinkle chopped fresh oregano over peppers before serving.