Spicy bean tostadas with pickled onions & radish salad - Good Food Middle East

Ingredients

• 2 red onions, 1 thinly sliced, 1 finely chopped
• 2 limes, juice of 1 and 1 cut into wedges
• 1½ tbsp sunflower oil
• 2 garlic cloves, finely chopped
• 2 tsp ground cumin
• 1 tbsp tomato purée
• 1 tbsp chipotle paste
• 400g can kidney beans, drained and rinsed
• 4 corn tortillas
• 140g radishes, thinly sliced
• large handful coriander, roughly chopped