Spray a small saucepan with low-calorie cooking spray and place over a medium heat. Add the onion and cook for 5 minutes until softened.
Add the garlic, chilli powder and smoked paprika, stir and cook for a further minute.
Lower the heat and add the black beans and the cold water. Stir, then cover and simmer gently for about 5 minutes. After 5 minutes, roughly mash the beans in the saucepan using a potato masher. Continue cooking with the lid off for a further 2-3 minutes, until all the liquid has reduced and you have a thick but spreadable mixture.
Stir in the lime juice, chopped coriander leaves and salt. Season to taste, with black pepper. Set aside.
Preheat the oven to 200°C.
In a small mixing bowl, mix together the avocado, tomatoes and lime juice. Season with salt and black pepper, to taste. Set aside.
Spray a large baking tray with low-calorie cooking spray and use to grease all over. Place the wraps in a single layer on the baking tray. Spray the wraps with low-calorie cooking spray and sprinkle with a pinch of salt.
Place the wraps in the preheated oven for 3-4 minutes until golden. Turn the wraps over and toast the other side for a further 3-4 minutes, or until golden and crisp. Place the toasted wraps on individual serving plates.
Place a medium saucepan of water on the stove, bring to a simmer and crack the eggs into the water. Poach the eggs to your liking.
While the eggs are poaching, divide the refried beans between the two toasted wraps. Spread over the wraps in an even layer.
Divide the salsa between the two wraps and spread over the refried beans. Divide the Cheddar cheese and sprinkle over the salsa.
Place a poached egg on top of each tostada and sprinkle a pinch of smoked paprika over the eggs.
Sprinkle roughly chopped coriander leaves over each tostada and serve immediately. Serve alone or with a crisp salad.