Place the washed spinach in a large saucepan and cook gently until wilted down – there's no need to add any water. Leave to cool, then squeeze out any excess water. Chop roughly.
Heat a little oil in a 23cm frying pan and gently cook one of the spring onions for a few minutes. Beat one of the eggs lightly, then add to the pan with a third of the spinach, a third of the cheddar and a few cherry tomato halves. Swirl the egg around the pan to make a very thin omelette. Cook for 3 minutes, then tip out of the pan straight on to a flour tortilla.
Roll up the tortilla and wrap in baking parchment, then foil. Repeat with the remaining ingredients until you have 3 wraps. To serve, cut each tortilla in half and unwrap the foil and parchment.