Tomato-Poached Fish With Chile Oil and Herbs

Ingredients

• 1/4 cup olive oil, plus more for drizzling
• 4 garlic cloves, thinly sliced
• 1 small shallot, thinly sliced into rings
• 1 teaspoon red-pepper flakes
• 1 pound small, sweet tomatoes, halved
• Kosher salt and black pepper
• 1 teaspoon fish sauce (optional)
• 1 1/4 pounds fluke, halibut or cod, cut into 4 equal pieces
• 1 cup cilantro, leaves and tender stems
• 1/2 cup mint, leaves and tender stems
• Limes, halved, for serving
• Tortillas, toast or rice, for serving (optional)