Cook the pasta according to the package directions. As soon as it's done cooking strain the pasta and run it under cold water to stop cooking and allow it to cool completely.
1/2 lb small pasta
In a large bowl, gently toss together all the veggies, pepperoni, cheese, basil, olives, and pasta to combine them.
1 cup cherry tomatoes, 1 small red onion, 1 green bell pepper, 1/2 cup pepperoni, 1 cup mozzarella pearls, 1-2 tbsp fresh basil, 1 2.25 oz can thinly sliced black olives
In a separate, smaller bowl, add in the garlic salt, oregano, tomato paste, vinegar, and olive oil. Briskly whisk the ingredients together until they're evenly incorporated and the dressing is smooth. Stir the dressing into the pasta salad and toss until evenly incorporated and everything's well coated. Salt and pepper the pasta salad, to taste.
1 tsp garlic powder, 1 tsp dried oregano, 2 1/2 - 3 heaping tbsp concentrated tomato paste, 2 tbsp red wine vinegar, 1/3 - 1/2 cup olive oil, salt and pepper
Allow to chill for 2 hours or overnight.