1 lb high-quality tuna steak (single piece, no blood lines)
1/4 cup black peppercorns, cracked
1 tbsp kosher salt
2 tsp safflower (or canola) oil
8 slices rye bread
Directions
For kraut, sauté onion in oil until translucent. Add fennel seed and wine. Heat until reduced by half. Add cabbage, sauerkraut, vinegar, and salt. Cover; cook 20 minutes. Remove lid; cook 20 minutes more, stirring often. For dressing, mix wasabi paste with yogurt; add cheese. Roll tuna in peppercorns, wrap in plastic and refrigerate 1 hour. Season tuna with salt. Heat a skillet until smoking, then add oil. Sear tuna on all sides; let rest 15 minutes; slice thinly. Toast bread, smear with dressing, and add kraut and tuna. Top with another slice of toast.
*Nonalcoholic option: Omit wine; increase vinegar to 1 cup.