Preheat an oven to 350 degrees F (175 degrees C). Oil a baking sheet.
Toss the pear halves in a bowl with the lemon juice, cinnamon, and 1 tablespoon of brown sugar. Place cut side down on prepared baking sheet. Brush pears with oil. Roast until caramelized and tender, 40 to 50 minutes. Remove from oven and let cool.
Meanwhile, mix together 1/4 cup brown sugar, maple syrup, mango, red onion, chili, garlic, ginger, dried cherries, cider vinegar, and cayenne pepper in a non-reactive saucepan. Bring to a boil, then reduce heat and simmer uncovered until liquid thickens to a syrup-like consistency and mangoes look translucent, 35 to 40 minutes. Remove from heat and let cool.
Coarsely chop pears and combine with the mango mixture. Cover and refrigerate 24 hours before serving.
