Sauté onion and garlic in hot oil in a Dutch oven over medium high heat until tender. Stir in chicken, Rotel, salt and pepper. Bring to a boil; reduce heat, and simmer, stirring occasionally, for 15 minutes. Remove from the heat and stir in cilantro and feta cheese.
Spoon about ¼ cup chicken mixture down center of each tortilla; roll up tortillas, and place, seam-side-down, in lightly greased 13x9 inch baking dish.
Whisk together half and half and cumin powder in a small saucepan over low heat until cumin is mixed in and liquid is warmed. (You can also heat it in the microwave for about 2 minutes). Pour over tortillas.
Bake, covered with foil, for 10 minutes. Remove foil and bake 10 more minutes. Sprinkle with shredded cheeses and cilantro (if using) bake 10 more minutes.