Healthier burritos

Name: Healthier burritos
Ingredients: 300g brown rice; 4-6 wholemeal tortilla wraps, to serve; 1 tsp olive oil; 400g-500g beef mince; 1 large onion, finely chopped; 2 garlic cloves, crushed; 2 tsp chipotle paste; 1 tbsp Cajun or fajita seasoning; 1 tbsp brown sugar; 1 tbsp cider vinegar; 400g can black beans, drained but not rinsed; 400g can chopped tomato; 1 tomato, chopped; 1 red onion, finely chopped; ½ small pack coriander, chopped; 1 lime, juiced; 2 avocados, stoned and peeled; natural yogurt, lime halves to squeeze over and grated cheddar (optional)