Heat olive oil in a Dutch oven (or other large heavy bottom pan) over medium. Pat chicken dry and season all over with kosher salt. When oil is shimmering, place chicken in pot, skin side down. Cook until browned and crispy 10-15 minutes. Remove from pan and set aside skin side up.
While chicken is searing, prepare yogurt and other ingredients. Mix vinegar, cumin, 1/2 tsp kosher salt, and crushed red pepper flakes (if using) with yogurt. Chop almonds and crush garlic cloves.
When chicken is done searing, reduce heat to medium-low and add garlic to pot. Cook 2 minutes. Add almonds, raisins, and chickpeas. Cook another 2-3 minutes until garlic is golden browned.
Add spiced yogurt and about 1/2 cup of water. Stir to combine. Nestle chicken legs into braise. Increase heat to medium and bring braise to a simmer, then reduce heat to low.
Simmer uncovered until chicken is tender and braise has slightly thickened, 20-30 minutes depending on the size of your chicken. Taste braising liquid and add more salt if necessary. Serve.