Preheat oven to 400°F. Toss the cherries with the sugar, flour, lemon juice, cinnamon, and salt in a large bowl. Coat a 2-quart baking dish with cooking spray (an 8-inch-by-8-inch dish works well). Spread the fruit mixture in the dish in an even layer.
Place the cookie crumbs in a food processor. Add the butter and pulse until cut into crumbs. Add the oats and pulse just until combined. Spread the cookie mixture evenly over the fruit. Cover loosely with foil and bake for 20 minutes. Uncover and bake for 20 to 30 minutes longer, or until the top is crisp.
Tip: Get a cherry pitter. Oxo makes an inexpensive handheld one that pits a pound of cherries in 5 minutes.