Heat oven to 350 degrees. Mist a 13- by 9-inch glass baking dish with nonstick cooking spray and set pan aside.
In 12-inch nonstick skillet, wilt beet greens over medium-high heat, tossing and stirring for about 3 minutes; add 1 tablespoon water if greens are sticking to the pan. Remove greens from heat to a bowl and set bowl aside to cool slightly.
Return skillet to the stove (no need to wash it), heat oil over medium heat and add onion and bell pepper. Sauté 5 minutes or until softened. Add garlic and sauté for another minute. Stir in drained pineapple, drained beans and green chiles. Mass cooled beet greens on a cutting board and chop more finely. Add half the greens to the skillet (save rest for another use) and cook and stir until everything is thoroughly heated. Remove skillet from heat. Stir in 1/3 cup cilantro, 2 cups of the cheese and 1/3 cup of the taco sauce.
Spoon 1/8 of vegetable mixture onto each tortilla. Roll up tortillas (no need to tuck ends in); place seam side down in prepared baking dish.
In small bowl, mix reserved 1/3 cup pineapple juice and remaining taco sauce; pour over entire surface of enchiladas in dish. Sprinkle with remaining 1 cup cheese. Spray sheet of foil large enough to cover baking dish with cooking spray; place sprayed side down over baking dish and seal.
Bake 40 minutes, remove foil and bake an additional 10-15 minutes.
Serve each baked enchilada with an additional sprinkling of fresh chopped cilantro if you wish.
The inspiration for this recipe came from Mary Buescher’s $10,000 winning recipe from the 2006 Pillsbury Bake-Off.
What should you do with the remaining 6 ounces of wilted beet greens? Stir them into tuna salad or egg salad at noon, or hummus dip for an appetizer dip, or into macaroni and cheese for dinner, or into your scrambled eggs in the morning.