Boy, Oh Boy, Black Bean Salad

Ingredients (9)

• + 2 tablespoons extra-virgin olive oil add to pantry
• + 1 onion, thinly sliced add to pantry
• ✓ 1 teaspoon kosher salt
• + ½ teaspoon red pepper flakes add to pantry
• ✓ ½ teaspoon ground black pepper
• ✓ 2 cloves garlic, chopped
• + 1 (15 ounce) can black beans, drained add to pantry
• + 1 (10 ounce) can diced tomatoes with green chile peppers add to pantry
• + 1 (10 ounce) bag fresh baby spinach add to pantry