Drain and rinse the black beans and tip into a large bowl. Peel and grate the garlic in, along with the lime zest. Squeeze in the juice.
Finely chop the coriander stalks (save the leaves for later). Peel and finely chop the red onion. Slide both into the black beans and stir in 1 tbsp oil and a pinch of salt and pepper.
Trim and slice the pattipans into 1cm slices. Bring a griddle or heavy frying pan to a high heat and pour in 1 tbsp oil. Add the pattipan slices and cook for 2 mins per side, till caramelised and lightly charred. Add to the beans.
Peel and stone the avocado and roughly chop. Toss the avocado into the salad.
Scoop the salad onto plates and crumble over half the pack of feta. Sprinkle over the remaining coriander leaves and serve.