Place meat on skewers. Preheat grill or grill pan to medium-high heat.
Heat 4 tablespoons EVOO in a small pan over medium-low heat. Add butter and melt. When it foams, add anchovies and melt them in. Add garlic and chilies, and stir 2 minutes; remove from heat.
Heat 4 tablespoons EVOO in a small pan over medium-low heat. Add butter and melt. When it foams, add anchovies and melt them in. Add garlic and chilies, and stir 2 minutes; remove from heat.
Coat onions and tomatoes with 1 tablespoon EVOO and grill onions for 12 minutes until charred at edges and softened; grill tomatoes 5-6 minutes to mark and blister.
Grill meat skewers for 2 minutes on each side, basting them with the anchovy butter.
Douse the bread in remaining butter and grill.
Chop tomatoes and combine them with the grilled onions, capers, olives, parsley, lemon juice, remaining tablespoon EVOO, salt and pepper. Pile salad over toast and top with beef.