Add oil to pan over medium-high heat. When the oil is hot enough, add shrimps and cook for 1-2 minutes on both sides or until they turn orange. Remove the shrimps from the pan and set aside once cooked.
Using the same pan, add more oil if necessary. Add garlic and cook until fragrant. Next, add sliced spring onions and cook for a few seconds.
Add rice to the pan and mix until the rice is warm. Take about 2-3 tbsp of tom yum paste and 1-2 tsp of chili paste then add them to the rice. Mix until even in color. You can do a taste test and add more tom yum paste and chili paste if necessary.
Season with salt. Add bok choi and tomatoes. Mix until bok choi is wilted.
Return the shrimps to the pan and mix again.