Add oil and onion to a medium non-stick frying pan over medium-high heat. Cook, stirring, for 2 minutes or until light golden. Add mince and cook, breaking up lumps, for 5-6 minutes, until no longer pink. Stir in chilli powder and tomatoes. Bring to the boil. Gently boil for 2-3 minutes or until thickened. Stir in coriander.
Meanwhile, heat rice cup in microwave, following packet instructions.
Divide mince mixture, rice, lettuce, capsicum and beans among 2 wide, shallow bowls. Dollop avocado on top. Sprinkle with feta and extra coriander. Serve with lime wedges.