Salsa Tatemada (Charred Roasted Salsa)

Ingredients

• A little olive oil
• 1 large onion (cut into 5-7 wedges)
• 1 red chile (serrano, sliced in half lengthways and seeded)
• 1 green jalapeño (sliced in half, seeded)
• 300-350 g cherry tomatoes ((0.7 lb.))
• 5 garlic cloves (whole in shells)
• 1/3 cup fresh coriander/cilantro
• 1 tablespoon lime juice
• 1/3 teaspoon salt