Wash cocktail potatoes and cut in half. If some are large, cut in quarters to ensure they’re all about the same size.
Drizzle olive oil in the bottom of a roasting pan, casserole dish, or baking sheet (with sides). Add potatoes, minced garlic, red pepper flakes, and a pinch of salt and pepper. Mix well with spoon or hands, and spread flat.
Roast in 400-degree oven for approximately 45 minutes. (Checking occasionally & flipping if necessary.)
Prepare another baking dish or sheet that is large enough for the tilapia and asparagus.
Drizzle baking dish with olive oil. Season tilapia with lemon juice, then add salt, pepper, and cayenne, and place in baking dish. After the potatoes have been cooking for 20 minutes, place tilapia in oven, and remove after 20-25 minutes.
Meanwhile, rinse asparagus and break off tough ends. (Discard ends or save for making stock later.) Drizzle with olive oil, salt, and pepper. In the last ten minutes of cooking time for the tilapia, place asparagus in the same baking dish, and bake for 10 minutes on 400 degrees fahrenheit.