Slow cooker black bean beef and rice

Name: Slow cooker black bean beef and rice
Ingredients: 250g/9oz beef mince; 170g/5¾oz sachet (or jar) black bean sauce; 4 tsp soy sauce; 1 onion, finely chopped; 1 large garlic clove, crushed; pinch chilli flakes, plus extra if spicier taste preferred (optional); 220g/8oz green beans, trimmed and halved; 400g tin black beans, drained and rinsed; 15g/½oz fresh coriander, stalks and leaves roughly chopped; freshly ground black pepper; 350g/12oz long-grain (or basmati) rice, cooked, to serve