Place 2 tbsp olive oil in a frying pan over medium to high heat. Add minced garlic and chopped onion, stir-fry until fragrant (about 1 minute).
Add in mushrooms, chicken sausages and fry for another 3-4 minutes. Add in cheese, and sprinkle some black pepper over filling. Remove from heat and allow to cool.
Take a spring roll wrapper and put it on a flat surface. Place it in an angle, so that it looks like a diamond. Spoon 2 tbsp of the filling, and add some diced cherry tomatoes on top of it> Then, fold the wrapper to enclose the filling. Then, fold in the the other 2 sides.
Heat oil for frying. Fry the spring rolls until golden brown for about 2-3 minutes. Drain on paper towels and keep warm. Serve with chilli sauce or a mustard dip.