In a large skillet cook ground turkey and jalapeno, if using, with half of the taco seasoning mix (about 2 tablespoons) until turkey is no longer pink; remove from heat and set aside.
Meanwhile, spread cream cheese into the bottom of a 13x9x2-inch baking dish. Spread cream cheese layer with refried beans. Stir the lemon juice into the mashed avocado and spread over refried bean layer. In a small bowl stir together sour cream, mayonnaise and remaining taco seasoning mix. Spread this sour cream mixture atop the avocado layer. Top with ground turkey mixture and then sprinkle top with cheese.
Bake, uncovered, in a 325 degrees F oven about 25 minutes or until heated through and cheese is evenly melted. Top with green onions if desired, shredded spinach and chopped tomato. Serve with vegetable dippers and/or baked tortilla chips.