Preheat oven to 400F.
In a skillet over medium heat, saute the chopped onion in 1 T olive oil until softened. Add the garlic and cook another 2-3 minutes. Set aside to cool slightly
In a separate bowl, add the sauteed onions and garlic, shredded chicken, corn, beans, green onion, cumin and cheese. Season to taste with salt and pepper.
Spoon approximately 1/4 cup filling onto a tortilla and roll up. Place seam side down in a baking dish or rimmed cookie sheet. Repeat, arranging the assembled taquitos in a single layer. Spray the tops with nonstick spray.
Bake for 20 minutes, or until the tops are crispy and browning.
In a small bowl, mash the avocado until smooth. Whisk in the ranch and adobo sauce and serve alongside for dipping.