Char onions in a hot pan over medium-high heat, turning occasionally, until dark brown. 

In a blender or food processor, puree onions, garlic, fennel seeds, coriander seeds, lemon juice, oil, and vinegar until sauce consistency. 

Preheat oven to 375°F. 

Drizzle beets with oil and wrap in foil. Place on baking sheet and roast for 40 minutes until tender. Cool beets. 

Place bread rounds on baking sheet and drizzle with oil. Toast 2 to 3 minutes, until crispy and lightly browned. Rub with clove of garlic. 

Peel beets by wiping the peel with a towel, it should just slide off. Dice beets, season with salt and pepper, and toss with vinaigrette. 

Spoon a little vinaigrette over baguette slices. Pile beets on baguette rounds. Garnish with radishes.