Heat oven to 350ºF.
Heat dressing in large nonstick skillet on medium-high heat. Add chicken; cook 6 minutes or until done, stirring occasionally. Remove from heat. Add rice and zest and mix lightly.
Spread tortillas with hummus; top with chicken mixture, cheese and spinach. Fold in opposite sides of each tortilla, then roll up burrito-style. Place, seam-sides down, in single layer in casserole.
Bake for 20 minutes or until heated through; top with yogurt and tomatoes.