Chilli Garlic Green Beans

• 1 tbsp extra virgin olive oil
• 1 brown onion, chopped
• 2 cloves of garlic, chopped
• 1 red chilli, chopped
• 2 tsp lemon zest
• 400 g green beans, ends trimmed
• 0.25 tsp salt
• 1 tsp toasted sesame seeds