Drain tomatoes, reserving 2/3 cup juice; set aside.
Drain artichokes, reserving 3/4 cup liquid; chop and set aside.
Cook tortellini according to package directions.
Meanwhile, in a large skillet, saute the onions, parsley, basil, garlic, oregano and pepper flakes in oil for 4-5 minutes or until onions are tender. Add the reserved tomatoes, tomato juice and artichoke liquid.
Bring to a boil. Reduce heat; simmer, uncovered, for 10-12 minutes or until slightly thickened.
Drain tortellini; add to tomato mixture.
Stir in the olives, salt and reserved artichokes; heat through.