Combine all ingredients for Prik Nam Pla and set aside in a small serving dish. Combine Soy sauce and Oyster sauce together and set aside in a small bowl.
Prep all ingredients prior to starting. In a large pan or wok, heat 1 Tbsp of oil over medium high heat. Cook chicken until done. Remove and set aside, wipe wok clean with a paper towel.
Add another tablespoon of oil over medium heat and add, diced onions, minced garlic, and white parts of the green onion. Saute for about a minute
Add Rice, break up any chunks and toss around. Move rice over to one side of wok or pan, and place egg on the empty side. Scramble egg, then toss with rice. Add soy sauce mixture and toss.
Lower heat, add sliced tomatoes, white pepper, and half of the green onions. Reserve the other half for garnish.
Plate fried rice with sliced cucumbers, lime wedges, and Prik Nam Pla on the side.