Wash and dry all produce. Peel, then cut shallots into 1/8-inch pieces.Thinly slice radishes.Cut tomato into 1/4-inch pieces.Add half the vinegar, 1/2 tsp (1 tsp) sugar and 1 tbsp (2 tbsp) oil to a large bowl . Season with salt and pepper, then stir to combine. Add radishes and half the shallots. Stir to coat.

Heat a large non-stick pan over medium-high heat. While the pan heats, cut and discard top 1 inch of lemongrass, leaving root end intact.Remove outer layer, then quarter lemongrass lengthwise. Using the back of a spoon or a heavy pot, forcefully tap lemongrass to bruise. Finely chop.

When the pan is hot, add 1 tbsp (2 tbsp) oil, then lemongrass and remaining shallots. Cook, stirring often, until golden-brown and fragrant, 1-2 min. Add chicken. Cook, breaking up chicken into smaller pieces, until no pink remains, 4-5 min.**Add sweet chili sauce, fish sauce and remaining vinegar. Season with salt and pepper, to taste. Cook, stirring often until fragrant, 30 sec.Remove from heat and let cool, 3-4 min.

Pick mint leaves from stems, then roughly chop.Stir half the mint into cooled chicken mixture.Add spring mix and tomatoes to the bowl with radishes and shallots. Toss to combine.

Divide salad between plates.Top with chicken mixture. Drizzle chili-garlic sauce over top.Sprinkle crispy shallots and remaining mint over top.