In small bowl combine yogurt, garlic, dill and salt; set aside.
In large skillet heat olive oil over medium heat. Sprinkle one side of salmon fillets with seasoning. Cook fillets in olive oil (covered) until meat thermometer reads 145 degrees F and fish flakes easily with fork, turning once.
To assemble wrap: Over one warmed tortilla spread heaping 1 Tbsp yogurt mixture; sprinkle with 1 Tbsp onion. In center of wrap, top with 2 slices tomato, 1/2 cup spinach and 1 salmon fillet. Fold two ends toward center and roll. Repeat with remaining wraps and ingredients.