Bring a large pot of water to a boil. Coarsely chop all but 4 artichoke hearts; set aside hearts. Place remaining hearts in a blender. Add vinegar, shallot, garlic, mustard, basil and oregano; season with salt and pepper. Turn on blender and slowly add oil until dressing is emulsified; set aside. Add orzo to boiling water and cook until al dente, about 8 minutes. Drain pasta and then rinse under cold water. Drain again and transfer to a bowl; add crabmeat, cherry tomatoes, sun-dried tomatoes, chives, parsley, reserved artichoke and dressing; toss. Divide among 4 plates. Leftovers are also delicious chilled.