Peel the green papaya with a vegetable peeler. Cut it in half lengthwise and scoop out the seeds.
Shred the papaya using a box grater or a mandoline into thin strips. Place in a large bowl.
In a small jar or bowl, combine lime juice, fish sauce, sliced chili, minced garlic, and brown sugar. Shake or stir until the sugar dissolves.
Pour the dressing over the shredded papaya. Toss well with your hands or tongs to coat evenly.
Add the cherry tomatoes and half the peanuts. Toss gently.
Taste and adjust with a pinch of salt or more lime juice if needed.
Top with remaining peanuts and fresh cilantro. Serve immediately, or cover and eat within 2 hours.