1. Over medium heat, preheat a small skillet. Toast cumin and coriander seeds until seeds have darkened, 1-2 minutes, stirring frequently. Cool completely. In a spice grinder, or with a mortar and pestle, grind seeds to a powder.
2. In a large bowl, combine ground beef, onion, jalapeno, garlic, ginger, cilantro, mint, salt, pepper, garam masala, and ground cumin and coriander; mix well. Cover; refrigerate 1 hour.
3. Form mixture into 4-5 in. logs. Thread onto skewers.
4. In a large skillet, heat oil over medium-high heat. Add kebabs, spacing 1/2-in. apart; cook until browned and crispy on the edges and meat is cooked through, 2-3 minutes per side. Repeat with remaining kebabs. Transfer to a paper towel-lined plate to drain. Serve immediately.