In a small bowl, stir together the chili powder, cumin and oregano.
In a nonstick frying pan over medium heat, add the ground turkey and onion. Cook until the turkey is browned and onion is clear. Drain well.
Add the spices to the turkey mix. Stir to mix evenly.
To serve, put a 1/4 cup of the turkey mixture in each tortilla.
Top each with 1 tablespoon cheese, 1/4 of the diced tomatoes, 1/2 cup shredded lettuce and 2 tablespoons salsa.
Fold in both sides of each tortilla up over the filling, and then roll to close.
Serve right away.