Zak Walters ducks out from the kitchen of his Oklahoma City restaurant, Sedalia’s, to hand deliver three jewel-toned slabs of tuna to the front counter. Streaked with beautiful white fat, set atop crisp turnips and marinated radicchio, those sashimi cuts gleam red like prime beef. Two guests, deep in conversation, stop to stare at the trompe l’oeil before them. Smiles tease the corners of their mouths.