This traditional Mexican fish dish pairs nicely with rice or roasted potatoes.
Heat oil in a large skillet over medium-high heat. Add onion; cook, stirring occasionally, until golden, 5 to 7 minutes. Add garlic and jalapenos; cook 1 minute.
Add tomatoes and 3/4 cup water; cook until almost evaporated, 6 to 8 minutes. Stir in olives and oregano.
Season snapper fillets with salt and pepper. Reduce heat to medium; nestle fish in sauce. Cover, and cook until fish is opaque, 5 to 7 minutes. Serve with lime wedges.