Beautiful Black Bean "Burgers"

Ingredients

• 3⁄4 cup/90 g spelt flour
• 1⁄2 small tomato, plus additional sliced tomato for serving
• 1⁄4 small red onion, plus additional sliced onion for serving
• 2 garlic cloves
• 1 tablespoon packed fresh oregano leaves
• 1 teaspoon ground coriander
• 1 teaspoon ground cumin
• 1⁄4 teaspoon cayenne pepper
• 3 cups/565 g cooked, well-drained black beans, divided
• Fine sea salt to taste
• 2 tablespoons extra-virgin olive oil